Str replace

Python String replace() Method



Description

Python string method replace() returns a copy of the string in which the occurrences of old have been replaced with new, optionally restricting the number of replacements to max.

Syntax

Following is the syntax for replace() method −

str.replace(old, new[, max])

Parameters

  • old − This is old substring to be replaced.

  • new − This is new substring, which would replace old substring.

  • max − If this optional argument max is given, only the first count occurrences are replaced.

Return Value

This method returns a copy of the string with all occurrences of substring old replaced by new. If the optional argument max is given, only the first count occurrences are replaced.

Example

The following example shows the usage of replace() method.

Live Demo

#!/usr/bin/python str = "this is string example....wow!!! this is really string" print str.replace("is", "was") print str.replace("is", "was", 3)

When we run above program, it produces following result −

thwas was string example....wow!!! thwas was really string thwas was string example....wow!!! thwas is really string

python_strings.htm

Sours: https://www.tutorialspoint.com/python/string_replace.htm

String.Replace Method

Definition

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Returns a new string in which all occurrences of a specified Unicode character or String in the current string are replaced with another specified Unicode character or String.

Overloads

Replace(Char, Char)

Returns a new string in which all occurrences of a specified Unicode character in this instance are replaced with another specified Unicode character.

Replace(String, String)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string.

Replace(String, String, StringComparison)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string, using the provided comparison type.

Replace(String, String, Boolean, CultureInfo)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string, using the provided culture and case sensitivity.

Replace(Char, Char)

Returns a new string in which all occurrences of a specified Unicode character in this instance are replaced with another specified Unicode character.

Parameters

oldChar
Char

The Unicode character to be replaced.

newChar
Char

The Unicode character to replace all occurrences of .

Returns

String

A string that is equivalent to this instance except that all instances of are replaced with . If is not found in the current instance, the method returns the current instance unchanged.

Examples

The following example creates a comma separated value list by substituting commas for the blanks between a series of numbers.

Remarks

This method performs an ordinal (case-sensitive and culture-insensitive) search to find .

Note

This method does not modify the value of the current instance. Instead, it returns a new string in which all occurrences of are replaced by .

Because this method returns the modified string, you can chain together successive calls to the Replace method to perform multiple replacements on the original string. Method calls are executed from left to right. The following example provides an illustration.

See also

Replace(String, String)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string.

Parameters

oldValue
String

The string to be replaced.

newValue
String

The string to replace all occurrences of .

Returns

String

A string that is equivalent to the current string except that all instances of are replaced with . If is not found in the current instance, the method returns the current instance unchanged.

Exceptions

Examples

The following example demonstrates how you can use the Replace method to correct a spelling error.

Remarks

If is , all occurrences of are removed.

Note

This method does not modify the value of the current instance. Instead, it returns a new string in which all occurrences of are replaced by .

This method performs an ordinal (case-sensitive and culture-insensitive) search to find .

Because this method returns the modified string, you can chain together successive calls to the Replace method to perform multiple replacements on the original string. Method calls are executed from left to right. The following example provides an illustration.

See also

Replace(String, String, StringComparison)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string, using the provided comparison type.

Parameters

oldValue
String

The string to be replaced.

newValue
String

The string to replace all occurrences of .

comparisonType
StringComparison

One of the enumeration values that determines how is searched within this instance.

Returns

String

A string that is equivalent to the current string except that all instances of are replaced with . If is not found in the current instance, the method returns the current instance unchanged.

Exceptions

Remarks

If is , all occurrences of are removed.

Note

This method does not modify the value of the current instance. Instead, it returns a new string in which all occurrences of are replaced by .

This method performs a search to find using the culture and case sensitivity described by .

Because this method returns the modified string, you can chain together successive calls to the Replace method to perform multiple replacements on the original string. Method calls are executed from left to right. The following example provides an illustration.

Replace(String, String, Boolean, CultureInfo)

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string, using the provided culture and case sensitivity.

Parameters

oldValue
String

The string to be replaced.

newValue
String

The string to replace all occurrences of .

ignoreCase
Boolean

to ignore casing when comparing; otherwise.

culture
CultureInfo

The culture to use when comparing. If is , the current culture is used.

Returns

String

A string that is equivalent to the current string except that all instances of are replaced with . If is not found in the current instance, the method returns the current instance unchanged.

Exceptions

Remarks

If is , all occurrences of are removed.

Note

This method does not modify the value of the current instance. Instead, it returns a new string in which all occurrences of are replaced by .

This method performs a search to find using the provided and case sensitivity.

Because this method returns the modified string, you can chain together successive calls to the Replace method to perform multiple replacements on the original string. Method calls are executed from left to right. The following example provides an illustration.

Sours: https://docs.microsoft.com/en-us/dotnet/api/system.string.replace
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Built-in Types¶

The following sections describe the standard types that are built into the interpreter.

The principal built-in types are numerics, sequences, mappings, classes, instances and exceptions.

Some collection classes are mutable. The methods that add, subtract, or rearrange their members in place, and don’t return a specific item, never return the collection instance itself but .

Some operations are supported by several object types; in particular, practically all objects can be compared for equality, tested for truth value, and converted to a string (with the function or the slightly different function). The latter function is implicitly used when an object is written by the function.

Truth Value Testing¶

Any object can be tested for truth value, for use in an or condition or as operand of the Boolean operations below.

By default, an object is considered true unless its class defines either a method that returns or a method that returns zero, when called with the object. 1 Here are most of the built-in objects considered false:

  • constants defined to be false: and .

  • zero of any numeric type: , , , ,

  • empty sequences and collections: , , , , ,

Operations and built-in functions that have a Boolean result always return or for false and or for true, unless otherwise stated. (Important exception: the Boolean operations and always return one of their operands.)

Boolean Operations — , , ¶

These are the Boolean operations, ordered by ascending priority:

Operation

Result

Notes

if x is false, then y, else x

(1)

if x is false, then x, else y

(2)

if x is false, then , else

(3)

Notes:

  1. This is a short-circuit operator, so it only evaluates the second argument if the first one is false.

  2. This is a short-circuit operator, so it only evaluates the second argument if the first one is true.

  3. has a lower priority than non-Boolean operators, so is interpreted as , and is a syntax error.

Comparisons¶

There are eight comparison operations in Python. They all have the same priority (which is higher than that of the Boolean operations). Comparisons can be chained arbitrarily; for example, is equivalent to , except that y is evaluated only once (but in both cases z is not evaluated at all when is found to be false).

This table summarizes the comparison operations:

Operation

Meaning

strictly less than

less than or equal

strictly greater than

greater than or equal

equal

not equal

object identity

negated object identity

Objects of different types, except different numeric types, never compare equal. The operator is always defined but for some object types (for example, class objects) is equivalent to . The , , and operators are only defined where they make sense; for example, they raise a exception when one of the arguments is a complex number.

Non-identical instances of a class normally compare as non-equal unless the class defines the method.

Instances of a class cannot be ordered with respect to other instances of the same class, or other types of object, unless the class defines enough of the methods , , , and (in general, and are sufficient, if you want the conventional meanings of the comparison operators).

The behavior of the and operators cannot be customized; also they can be applied to any two objects and never raise an exception.

Two more operations with the same syntactic priority, and , are supported by types that are iterable or implement the method.

Numeric Types — , , ¶

There are three distinct numeric types: integers, floating point numbers, and complex numbers. In addition, Booleans are a subtype of integers. Integers have unlimited precision. Floating point numbers are usually implemented using double in C; information about the precision and internal representation of floating point numbers for the machine on which your program is running is available in . Complex numbers have a real and imaginary part, which are each a floating point number. To extract these parts from a complex number z, use and . (The standard library includes the additional numeric types , for rationals, and , for floating-point numbers with user-definable precision.)

Numbers are created by numeric literals or as the result of built-in functions and operators. Unadorned integer literals (including hex, octal and binary numbers) yield integers. Numeric literals containing a decimal point or an exponent sign yield floating point numbers. Appending or to a numeric literal yields an imaginary number (a complex number with a zero real part) which you can add to an integer or float to get a complex number with real and imaginary parts.

Python fully supports mixed arithmetic: when a binary arithmetic operator has operands of different numeric types, the operand with the “narrower” type is widened to that of the other, where integer is narrower than floating point, which is narrower than complex. A comparison between numbers of different types behaves as though the exact values of those numbers were being compared. 2

The constructors , , and can be used to produce numbers of a specific type.

All numeric types (except complex) support the following operations (for priorities of the operations, see Operator precedence):

Operation

Result

Notes

Full documentation

sum of x and y

difference of x and y

product of x and y

quotient of x and y

floored quotient of x and y

(1)

remainder of

(2)

x negated

x unchanged

absolute value or magnitude of x

x converted to integer

(3)(6)

x converted to floating point

(4)(6)

a complex number with real part re, imaginary part im. im defaults to zero.

(6)

conjugate of the complex number c

the pair

(2)

x to the power y

(5)

x to the power y

(5)

Notes:

  1. Also referred to as integer division. The resultant value is a whole integer, though the result’s type is not necessarily int. The result is always rounded towards minus infinity: is , is , is , and is .

  2. Not for complex numbers. Instead convert to floats using if appropriate.

  3. Conversion from floating point to integer may round or truncate as in C; see functions and for well-defined conversions.

  4. float also accepts the strings “nan” and “inf” with an optional prefix “+” or “-” for Not a Number (NaN) and positive or negative infinity.

  5. Python defines and to be , as is common for programming languages.

  6. The numeric literals accepted include the digits to or any Unicode equivalent (code points with the property).

    See https://www.unicode.org/Public/13.0.0/ucd/extracted/DerivedNumericType.txt for a complete list of code points with the property.

All types ( and ) also include the following operations:

For additional numeric operations see the and modules.

Bitwise Operations on Integer Types¶

Bitwise operations only make sense for integers. The result of bitwise operations is calculated as though carried out in two’s complement with an infinite number of sign bits.

The priorities of the binary bitwise operations are all lower than the numeric operations and higher than the comparisons; the unary operation has the same priority as the other unary numeric operations ( and ).

This table lists the bitwise operations sorted in ascending priority:

Operation

Result

Notes

bitwise or of x and y

(4)

bitwise exclusive or of x and y

(4)

bitwise and of x and y

(4)

x shifted left by n bits

(1)(2)

x shifted right by n bits

(1)(3)

the bits of x inverted

Notes:

  1. Negative shift counts are illegal and cause a to be raised.

  2. A left shift by n bits is equivalent to multiplication by .

  3. A right shift by n bits is equivalent to floor division by .

  4. Performing these calculations with at least one extra sign extension bit in a finite two’s complement representation (a working bit-width of or more) is sufficient to get the same result as if there were an infinite number of sign bits.

Additional Methods on Integer Types¶

The int type implements the abstract base class. In addition, it provides a few more methods:

()¶

Return the number of bits necessary to represent an integer in binary, excluding the sign and leading zeros:

>>> n=-37>>> bin(n)'-0b100101'>>> n.bit_length()6

More precisely, if is nonzero, then is the unique positive integer such that . Equivalently, when is small enough to have a correctly rounded logarithm, then . If is zero, then returns .

Equivalent to:

defbit_length(self):s=bin(self)# binary representation: bin(-37) --> '-0b100101's=s.lstrip('-0b')# remove leading zeros and minus signreturnlen(s)# len('100101') --> 6
()¶

Return the number of ones in the binary representation of the absolute value of the integer. This is also known as the population count. Example:

>>> n=19>>> bin(n)'0b10011'>>> n.bit_count()3>>> (-n).bit_count()3

Equivalent to:

defbit_count(self):returnbin(self).count("1")
(length, byteorder, *, signed=False

Return an array of bytes representing an integer.

>>> (1024).to_bytes(2,byteorder='big')b'\x04\x00'>>> (1024).to_bytes(10,byteorder='big')b'\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00'>>> (-1024).to_bytes(10,byteorder='big',signed=True)b'\xff\xff\xff\xff\xff\xff\xff\xff\xfc\x00'>>> x=1000>>> x.to_bytes((x.bit_length()+7)//8,byteorder='little')b'\xe8\x03'

The integer is represented using length bytes. An is raised if the integer is not representable with the given number of bytes.

The byteorder argument determines the byte order used to represent the integer. If byteorder is , the most significant byte is at the beginning of the byte array. If byteorder is , the most significant byte is at the end of the byte array. To request the native byte order of the host system, use as the byte order value.

The signed argument determines whether two’s complement is used to represent the integer. If signed is and a negative integer is given, an is raised. The default value for signed is .

classmethod (bytes, byteorder, *, signed=False

Return the integer represented by the given array of bytes.

>>> int.from_bytes(b'\x00\x10',byteorder='big')16>>> int.from_bytes(b'\x00\x10',byteorder='little')4096>>> int.from_bytes(b'\xfc\x00',byteorder='big',signed=True)-1024>>> int.from_bytes(b'\xfc\x00',byteorder='big',signed=False)64512>>> int.from_bytes([255,0,0],byteorder='big')16711680

The argument bytes must either be a bytes-like object or an iterable producing bytes.

The byteorder argument determines the byte order used to represent the integer. If byteorder is , the most significant byte is at the beginning of the byte array. If byteorder is , the most significant byte is at the end of the byte array. To request the native byte order of the host system, use as the byte order value.

The signed argument indicates whether two’s complement is used to represent the integer.

()¶

Return a pair of integers whose ratio is exactly equal to the original integer and with a positive denominator. The integer ratio of integers (whole numbers) is always the integer as the numerator and as the denominator.

Additional Methods on Float¶

The float type implements the abstract base class. float also has the following additional methods.

()¶

Return a pair of integers whose ratio is exactly equal to the original float and with a positive denominator. Raises on infinities and a on NaNs.

()¶

Return if the float instance is finite with integral value, and otherwise:

>>> (-2.0).is_integer()True>>> (3.2).is_integer()False

Two methods support conversion to and from hexadecimal strings. Since Python’s floats are stored internally as binary numbers, converting a float to or from a decimal string usually involves a small rounding error. In contrast, hexadecimal strings allow exact representation and specification of floating-point numbers. This can be useful when debugging, and in numerical work.

()¶

Return a representation of a floating-point number as a hexadecimal string. For finite floating-point numbers, this representation will always include a leading and a trailing and exponent.

classmethod (s

Class method to return the float represented by a hexadecimal string s. The string s may have leading and trailing whitespace.

Note that is an instance method, while is a class method.

A hexadecimal string takes the form:

[sign]['0x']integer['.'fraction]['p'exponent]

where the optional may by either or , and are strings of hexadecimal digits, and is a decimal integer with an optional leading sign. Case is not significant, and there must be at least one hexadecimal digit in either the integer or the fraction. This syntax is similar to the syntax specified in section 6.4.4.2 of the C99 standard, and also to the syntax used in Java 1.5 onwards. In particular, the output of is usable as a hexadecimal floating-point literal in C or Java code, and hexadecimal strings produced by C’s format character or Java’s are accepted by .

Note that the exponent is written in decimal rather than hexadecimal, and that it gives the power of 2 by which to multiply the coefficient. For example, the hexadecimal string represents the floating-point number , or :

>>> float.fromhex('0x3.a7p10')3740.0

Applying the reverse conversion to gives a different hexadecimal string representing the same number:

>>> float.hex(3740.0)'0x1.d380000000000p+11'

Hashing of numeric types¶

For numbers and , possibly of different types, it’s a requirement that whenever (see the method documentation for more details). For ease of implementation and efficiency across a variety of numeric types (including , , and ) Python’s hash for numeric types is based on a single mathematical function that’s defined for any rational number, and hence applies to all instances of and , and all finite instances of and . Essentially, this function is given by reduction modulo for a fixed prime . The value of is made available to Python as the attribute of .

CPython implementation detail: Currently, the prime used is on machines with 32-bit C longs and on machines with 64-bit C longs.

Here are the rules in detail:

  • If is a nonnegative rational number and is not divisible by , define as , where gives the inverse of modulo .

  • If is a nonnegative rational number and is divisible by (but is not) then has no inverse modulo and the rule above doesn’t apply; in this case define to be the constant value .

  • If is a negative rational number define as . If the resulting hash is , replace it with .

  • The particular values and are used as hash values for positive infinity or negative infinity (respectively).

  • For a number , the hash values of the real and imaginary parts are combined by computing , reduced modulo so that it lies in . Again, if the result is , it’s replaced with .

To clarify the above rules, here’s some example Python code, equivalent to the built-in hash, for computing the hash of a rational number, , or :

importsys,mathdefhash_fraction(m,n):"""Compute the hash of a rational number m / n. Assumes m and n are integers, with n positive. Equivalent to hash(fractions.Fraction(m, n)). """P=sys.hash_info.modulus# Remove common factors of P. (Unnecessary if m and n already coprime.)whilem%P==n%P==0:m,n=m//P,n//Pifn%P==0:hash_value=sys.hash_info.infelse:# Fermat's Little Theorem: pow(n, P-1, P) is 1, so# pow(n, P-2, P) gives the inverse of n modulo P.hash_value=(abs(m)%P)*pow(n,P-2,P)%Pifm<0:hash_value=-hash_valueifhash_value==-1:hash_value=-2returnhash_valuedefhash_float(x):"""Compute the hash of a float x."""ifmath.isnan(x):returnobject.__hash__(x)elifmath.isinf(x):returnsys.hash_info.infifx>0else-sys.hash_info.infelse:returnhash_fraction(*x.as_integer_ratio())defhash_complex(z):"""Compute the hash of a complex number z."""hash_value=hash_float(z.real)+sys.hash_info.imag*hash_float(z.imag)# do a signed reduction modulo 2**sys.hash_info.widthM=2**(sys.hash_info.width-1)hash_value=(hash_value&(M-1))-(hash_value&M)ifhash_value==-1:hash_value=-2returnhash_value

Iterator Types¶

Python supports a concept of iteration over containers. This is implemented using two distinct methods; these are used to allow user-defined classes to support iteration. Sequences, described below in more detail, always support the iteration methods.

One method needs to be defined for container objects to provide iteration support:

()¶

Return an iterator object. The object is required to support the iterator protocol described below. If a container supports different types of iteration, additional methods can be provided to specifically request iterators for those iteration types. (An example of an object supporting multiple forms of iteration would be a tree structure which supports both breadth-first and depth-first traversal.) This method corresponds to the slot of the type structure for Python objects in the Python/C API.

The iterator objects themselves are required to support the following two methods, which together form the iterator protocol:

()¶

Return the iterator object itself. This is required to allow both containers and iterators to be used with the and statements. This method corresponds to the slot of the type structure for Python objects in the Python/C API.

()¶

Return the next item from the container. If there are no further items, raise the exception. This method corresponds to the slot of the type structure for Python objects in the Python/C API.

Python defines several iterator objects to support iteration over general and specific sequence types, dictionaries, and other more specialized forms. The specific types are not important beyond their implementation of the iterator protocol.

Once an iterator’s method raises , it must continue to do so on subsequent calls. Implementations that do not obey this property are deemed broken.

Generator Types¶

Python’s generators provide a convenient way to implement the iterator protocol. If a container object’s method is implemented as a generator, it will automatically return an iterator object (technically, a generator object) supplying the and methods. More information about generators can be found in the documentation for the yield expression.

Sequence Types — , , ¶

There are three basic sequence types: lists, tuples, and range objects. Additional sequence types tailored for processing of binary data and text strings are described in dedicated sections.

Common Sequence Operations¶

The operations in the following table are supported by most sequence types, both mutable and immutable. The ABC is provided to make it easier to correctly implement these operations on custom sequence types.

This table lists the sequence operations sorted in ascending priority. In the table, s and t are sequences of the same type, n, i, j and k are integers and x is an arbitrary object that meets any type and value restrictions imposed by s.

The and operations have the same priorities as the comparison operations. The (concatenation) and (repetition) operations have the same priority as the corresponding numeric operations. 3

Operation

Result

Notes

if an item of s is equal to x, else

(1)

if an item of s is equal to x, else

(1)

the concatenation of s and t

(6)(7)

or

equivalent to adding s to itself n times

(2)(7)

ith item of s, origin 0

(3)

slice of s from i to j

(3)(4)

slice of s from i to j with step k

(3)(5)

length of s

smallest item of s

largest item of s

index of the first occurrence of x in s (at or after index i and before index j)

(8)

total number of occurrences of x in s

Sequences of the same type also support comparisons. In particular, tuples and lists are compared lexicographically by comparing corresponding elements. This means that to compare equal, every element must compare equal and the two sequences must be of the same type and have the same length. (For full details see Comparisons in the language reference.)

Notes:

  1. While the and operations are used only for simple containment testing in the general case, some specialised sequences (such as , and ) also use them for subsequence testing:

    >>> "gg"in"eggs"True
  2. Values of n less than are treated as (which yields an empty sequence of the same type as s). Note that items in the sequence s are not copied; they are referenced multiple times. This often haunts new Python programmers; consider:

    >>> lists=[[]]*3>>> lists[[], [], []]>>> lists[0].append(3)>>> lists[[3], [3], [3]]

    What has happened is that is a one-element list containing an empty list, so all three elements of are references to this single empty list. Modifying any of the elements of modifies this single list. You can create a list of different lists this way:

    >>> lists=[[]foriinrange(3)]>>> lists[0].append(3)>>> lists[1].append(5)>>> lists[2].append(7)>>> lists[[3], [5], [7]]

    Further explanation is available in the FAQ entry How do I create a multidimensional list?.

  3. If i or j is negative, the index is relative to the end of sequence s: or is substituted. But note that is still .

  4. The slice of s from i to j is defined as the sequence of items with index k such that . If i or j is greater than , use . If i is omitted or , use . If j is omitted or , use . If i is greater than or equal to j, the slice is empty.

  5. The slice of s from i to j with step k is defined as the sequence of items with index such that . In other words, the indices are , , , and so on, stopping when j is reached (but never including j). When k is positive, i and j are reduced to if they are greater. When k is negative, i and j are reduced to if they are greater. If i or j are omitted or , they become “end” values (which end depends on the sign of k). Note, k cannot be zero. If k is , it is treated like .

  6. Concatenating immutable sequences always results in a new object. This means that building up a sequence by repeated concatenation will have a quadratic runtime cost in the total sequence length. To get a linear runtime cost, you must switch to one of the alternatives below:

    • if concatenating objects, you can build a list and use at the end or else write to an instance and retrieve its value when complete

    • if concatenating objects, you can similarly use or , or you can do in-place concatenation with a object. objects are mutable and have an efficient overallocation mechanism

    • if concatenating objects, extend a instead

    • for other types, investigate the relevant class documentation

  7. Some sequence types (such as ) only support item sequences that follow specific patterns, and hence don’t support sequence concatenation or repetition.

  8. raises when x is not found in s. Not all implementations support passing the additional arguments i and j. These arguments allow efficient searching of subsections of the sequence. Passing the extra arguments is roughly equivalent to using , only without copying any data and with the returned index being relative to the start of the sequence rather than the start of the slice.

Immutable Sequence Types¶

The only operation that immutable sequence types generally implement that is not also implemented by mutable sequence types is support for the built-in.

This support allows immutable sequences, such as instances, to be used as keys and stored in and instances.

Attempting to hash an immutable sequence that contains unhashable values will result in .

Mutable Sequence Types¶

The operations in the following table are defined on mutable sequence types. The ABC is provided to make it easier to correctly implement these operations on custom sequence types.

In the table s is an instance of a mutable sequence type, t is any iterable object and x is an arbitrary object that meets any type and value restrictions imposed by s (for example, only accepts integers that meet the value restriction ).

Operation

Result

Notes

item i of s is replaced by x

slice of s from i to j is replaced by the contents of the iterable t

same as

the elements of are replaced by those of t

(1)

removes the elements of from the list

appends x to the end of the sequence (same as )

removes all items from s (same as )

(5)

creates a shallow copy of s (same as )

(5)

or

extends s with the contents of t (for the most part the same as )

updates s with its contents repeated n times

(6)

inserts x into s at the index given by i (same as )

or

retrieves the item at i and also removes it from s

(2)

remove the first item from s where is equal to x

(3)

reverses the items of s in place

(4)

Notes:

  1. t must have the same length as the slice it is replacing.

  2. The optional argument i defaults to , so that by default the last item is removed and returned.

  3. raises when x is not found in s.

  4. The method modifies the sequence in place for economy of space when reversing a large sequence. To remind users that it operates by side effect, it does not return the reversed sequence.

  5. and are included for consistency with the interfaces of mutable containers that don’t support slicing operations (such as and ). is not part of the ABC, but most concrete mutable sequence classes provide it.

    New in version 3.3: and methods.

  6. The value n is an integer, or an object implementing . Zero and negative values of n clear the sequence. Items in the sequence are not copied; they are referenced multiple times, as explained for under Common Sequence Operations.

Lists¶

Lists are mutable sequences, typically used to store collections of homogeneous items (where the precise degree of similarity will vary by application).

class ([iterable])¶

Lists may be constructed in several ways:

  • Using a pair of square brackets to denote the empty list:

  • Using square brackets, separating items with commas: ,

  • Using a list comprehension:

  • Using the type constructor: or

The constructor builds a list whose items are the same and in the same order as iterable’s items. iterable may be either a sequence, a container that supports iteration, or an iterator object. If iterable is already a list, a copy is made and returned, similar to . For example, returns and returns . If no argument is given, the constructor creates a new empty list, .

Many other operations also produce lists, including the built-in.

Lists implement all of the common and mutable sequence operations. Lists also provide the following additional method:

(*, key=None, reverse=False

This method sorts the list in place, using only comparisons between items. Exceptions are not suppressed - if any comparison operations fail, the entire sort operation will fail (and the list will likely be left in a partially modified state).

accepts two arguments that can only be passed by keyword (keyword-only arguments):

key specifies a function of one argument that is used to extract a comparison key from each list element (for example, ). The key corresponding to each item in the list is calculated once and then used for the entire sorting process. The default value of means that list items are sorted directly without calculating a separate key value.

The utility is available to convert a 2.x style cmp function to a key function.

reverse is a boolean value. If set to , then the list elements are sorted as if each comparison were reversed.

This method modifies the sequence in place for economy of space when sorting a large sequence. To remind users that it operates by side effect, it does not return the sorted sequence (use to explicitly request a new sorted list instance).

The method is guaranteed to be stable. A sort is stable if it guarantees not to change the relative order of elements that compare equal — this is helpful for sorting in multiple passes (for example, sort by department, then by salary grade).

For sorting examples and a brief sorting tutorial, see Sorting HOW TO.

CPython implementation detail: While a list is being sorted, the effect of attempting to mutate, or even inspect, the list is undefined. The C implementation of Python makes the list appear empty for the duration, and raises if it can detect that the list has been mutated during a sort.

Tuples¶

Tuples are immutable sequences, typically used to store collections of heterogeneous data (such as the 2-tuples produced by the built-in). Tuples are also used for cases where an immutable sequence of homogeneous data is needed (such as allowing storage in a or instance).

class ([iterable])¶

Tuples may be constructed in a number of ways:

  • Using a pair of parentheses to denote the empty tuple:

  • Using a trailing comma for a singleton tuple: or

  • Separating items with commas: or

  • Using the built-in: or

The constructor builds a tuple whose items are the same and in the same order as iterable’s items. iterable may be either a sequence, a container that supports iteration, or an iterator object. If iterable is already a tuple, it is returned unchanged. For example, returns and returns . If no argument is given, the constructor creates a new empty tuple, .

Note that it is actually the comma which makes a tuple, not the parentheses. The parentheses are optional, except in the empty tuple case, or when they are needed to avoid syntactic ambiguity. For example, is a function call with three arguments, while is a function call with a 3-tuple as the sole argument.

Tuples implement all of the common sequence operations.

For heterogeneous collections of data where access by name is clearer than access by index, may be a more appropriate choice than a simple tuple object.

Ranges¶

The type represents an immutable sequence of numbers and is commonly used for looping a specific number of times in loops.

class (stop
class (start, stop[, step])

The arguments to the range constructor must be integers (either built-in or any object that implements the special method). If the step argument is omitted, it defaults to . If the start argument is omitted, it defaults to . If step is zero, is raised.

For a positive step, the contents of a range are determined by the formula where and .

For a negative step, the contents of the range are still determined by the formula , but the constraints are and .

A range object will be empty if does not meet the value constraint. Ranges do support negative indices, but these are interpreted as indexing from the end of the sequence determined by the positive indices.

Ranges containing absolute values larger than are permitted but some features (such as ) may raise .

Range examples:

>>> list(range(10))[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]>>> list(range(1,11))[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]>>> list(range(0,30,5))[0, 5, 10, 15, 20, 25]>>> list(range(0,10,3))[0, 3, 6, 9]>>> list(range(0,-10,-1))[0, -1, -2, -3, -4, -5, -6, -7, -8, -9]>>> list(range(0))[]>>> list(range(1,0))[]

Ranges implement all of the common sequence operations except concatenation and repetition (due to the fact that range objects can only represent sequences that follow a strict pattern and repetition and concatenation will usually violate that pattern).

The value of the start parameter (or if the parameter was not supplied)

The value of the stop parameter

The value of the step parameter (or if the parameter was not supplied)

The advantage of the type over a regular or is that a object will always take the same (small) amount of memory, no matter the size of the range it represents (as it only stores the , and values, calculating individual items and subranges as needed).

Range objects implement the ABC, and provide features such as containment tests, element index lookup, slicing and support for negative indices (see Sequence Types — list, tuple, range):

>>> r=range(0,20,2)>>> rrange(0, 20, 2)>>> 11inrFalse>>> 10inrTrue>>> r.index(10)5>>> r[5]10>>> r[:5]range(0, 10, 2)>>> r[-1]18

Testing range objects for equality with and compares them as sequences. That is, two range objects are considered equal if they represent the same sequence of values. (Note that two range objects that compare equal might have different , and attributes, for example or .)

Changed in version 3.2: Implement the Sequence ABC. Support slicing and negative indices. Test objects for membership in constant time instead of iterating through all items.

Changed in version 3.3: Define ‘==’ and ‘!=’ to compare range objects based on the sequence of values they define (instead of comparing based on object identity).

See also

  • The linspace recipe shows how to implement a lazy version of range suitable for floating point applications.

Text Sequence Type — ¶

Textual data in Python is handled with objects, or strings. Strings are immutable sequences of Unicode code points. String literals are written in a variety of ways:

  • Single quotes:

  • Double quotes: .

  • Triple quoted: ,

Triple quoted strings may span multiple lines - all associated whitespace will be included in the string literal.

String literals that are part of a single expression and have only whitespace between them will be implicitly converted to a single string literal. That is, .

See String and Bytes literals for more about the various forms of string literal, including supported escape sequences, and the (“raw”) prefix that disables most escape sequence processing.

Strings may also be created from other objects using the constructor.

Since there is no separate “character” type, indexing a string produces strings of length 1. That is, for a non-empty string s, .

There is also no mutable string type, but or can be used to efficiently construct strings from multiple fragments.

Changed in version 3.3: For backwards compatibility with the Python 2 series, the prefix is once again permitted on string literals. It has no effect on the meaning of string literals and cannot be combined with the prefix.

class (object=''
class (object=b'', encoding='utf-8', errors='strict')

Return a string version of object. If object is not provided, returns the empty string. Otherwise, the behavior of depends on whether encoding or errors is given, as follows.

If neither encoding nor errors is given, returns , which is the “informal” or nicely printable string representation of object. For string objects, this is the string itself. If object does not have a method, then falls back to returning .

If at least one of encoding or errors is given, object should be a bytes-like object (e.g. or ). In this case, if object is a (or ) object, then is equivalent to . Otherwise, the bytes object underlying the buffer object is obtained before calling . See Binary Sequence Types — bytes, bytearray, memoryview and Buffer Protocol for information on buffer objects.

Passing a object to without the encoding or errors arguments falls under the first case of returning the informal string representation (see also the command-line option to Python). For example:

>>> str(b'Zoot!')"b'Zoot!'"

For more information on the class and its methods, see Text Sequence Type — str and the String Methods section below. To output formatted strings, see the Formatted string literals and Format String Syntax sections. In addition, see the Text Processing Services section.

String Methods¶

Strings implement all of the common sequence operations, along with the additional methods described below.

Strings also support two styles of string formatting, one providing a large degree of flexibility and customization (see , Format String Syntax and Custom String Formatting) and the other based on C style formatting that handles a narrower range of types and is slightly harder to use correctly, but is often faster for the cases it can handle (printf-style String Formatting).

The Text Processing Services section of the standard library covers a number of other modules that provide various text related utilities (including regular expression support in the module).

()¶

Return a copy of the string with its first character capitalized and the rest lowercased.

Changed in version 3.8: The first character is now put into titlecase rather than uppercase. This means that characters like digraphs will only have their first letter capitalized, instead of the full character.

()¶

Return a casefolded copy of the string. Casefolded strings may be used for caseless matching.

Casefolding is similar to lowercasing but more aggressive because it is intended to remove all case distinctions in a string. For example, the German lowercase letter is equivalent to . Since it is already lowercase, would do nothing to ; converts it to .

The casefolding algorithm is described in section 3.13 of the Unicode Standard.

(width[, fillchar])¶

Return centered in a string of length width. Padding is done using the specified fillchar (default is an ASCII space). The original string is returned if width is less than or equal to .

(sub[, start[, end]])¶

Return the number of non-overlapping occurrences of substring sub in the range [start, end]. Optional arguments start and end are interpreted as in slice notation.

(encoding='utf-8', errors='strict'

Return an encoded version of the string as a bytes object. Default encoding is . errors may be given to set a different error handling scheme. The default for errors is , meaning that encoding errors raise a . Other possible values are , , , and any other name registered via , see section Error Handlers. For a list of possible encodings, see section Standard Encodings.

By default, the errors argument is not checked for best performances, but only used at the first encoding error. Enable the Python Development Mode, or use a debug build to check errors.

Changed in version 3.1: Support for keyword arguments added.

Changed in version 3.9: The errors is now checked in development mode and in debug mode.

(suffix[, start[, end]])¶

Return if the string ends with the specified suffix, otherwise return . suffix can also be a tuple of suffixes to look for. With optional start, test beginning at that position. With optional end, stop comparing at that position.

(tabsize=8

Return a copy of the string where all tab characters are replaced by one or more spaces, depending on the current column and the given tab size. Tab positions occur every tabsize characters (default is 8, giving tab positions at columns 0, 8, 16 and so on). To expand the string, the current column is set to zero and the string is examined character by character. If the character is a tab (), one or more space characters are inserted in the result until the current column is equal to the next tab position. (The tab character itself is not copied.) If the character is a newline () or return (), it is copied and the current column is reset to zero. Any other character is copied unchanged and the current column is incremented by one regardless of how the character is represented when printed.

>>> '01\t012\t0123\t01234'.expandtabs()'01 012 0123 01234'>>> '01\t012\t0123\t01234'.expandtabs(4)'01 012 0123 01234'
(sub[, start[, end]])¶

Return the lowest index in the string where substring sub is found within the slice . Optional arguments start and end are interpreted as in slice notation. Return if sub is not found.

Note

The method should be used only if you need to know the position of sub. To check if sub is a substring or not, use the operator:

>>> 'Py'in'Python'True
(*args, **kwargs

Perform a string formatting operation. The string on which this method is called can contain literal text or replacement fields delimited by braces . Each replacement field contains either the numeric index of a positional argument, or the name of a keyword argument. Returns a copy of the string where each replacement field is replaced with the string value of the corresponding argument.

>>> "The sum of 1 + 2 is {0}".format(1+2)'The sum of 1 + 2 is 3'

See Format String Syntax for a description of the various formatting options that can be specified in format strings.

Note

When formatting a number (, , , and subclasses) with the type (ex: ), the function temporarily sets the locale to the locale to decode and fields of if they are non-ASCII or longer than 1 byte, and the locale is different than the locale. This temporary change affects other threads.

Changed in version 3.7: When formatting a number with the type, the function sets temporarily the locale to the locale in some cases.

(mapping

Similar to , except that is used directly and not copied to a . This is useful if for example is a dict subclass:

>>> classDefault(dict):... def__missing__(self,key):... returnkey...>>> '{name} was born in {country}'.format_map(Default(name='Guido'))'Guido was born in country'
(sub[, start[, end]])¶

Like , but raise when the substring is not found.

()¶

Return if all characters in the string are alphanumeric and there is at least one character, otherwise. A character is alphanumeric if one of the following returns : , , , or .

()¶

Return if all characters in the string are alphabetic and there is at least one character, otherwise. Alphabetic characters are those characters defined in the Unicode character database as “Letter”, i.e., those with general category property being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”. Note that this is different from the “Alphabetic” property defined in the Unicode Standard.

()¶

Return if the string is empty or all characters in the string are ASCII, otherwise. ASCII characters have code points in the range U+0000-U+007F.

()¶

Return if all characters in the string are decimal characters and there is at least one character, otherwise. Decimal characters are those that can be used to form numbers in base 10, e.g. U+0660, ARABIC-INDIC DIGIT ZERO. Formally a decimal character is a character in the Unicode General Category “Nd”.

()¶

Return if all characters in the string are digits and there is at least one character, otherwise. Digits include decimal characters and digits that need special handling, such as the compatibility superscript digits. This covers digits which cannot be used to form numbers in base 10, like the Kharosthi numbers. Formally, a digit is a character that has the property value Numeric_Type=Digit or Numeric_Type=Decimal.

Return if the string is a valid identifier according to the language definition, section Identifiers and keywords.

Call to test whether string is a reserved identifier, such as and .

Example:

>>> fromkeywordimportiskeyword>>> 'hello'.isidentifier(),iskeyword('hello')True, False>>> 'def'.isidentifier(),iskeyword('def')True, True
()¶

Return if all cased characters 4 in the string are lowercase and there is at least one cased character, otherwise.

()¶

Return if all characters in the string are numeric characters, and there is at least one character, otherwise. Numeric characters include digit characters, and all characters that have the Unicode numeric value property, e.g. U+2155, VULGAR FRACTION ONE FIFTH. Formally, numeric characters are those with the property value Numeric_Type=Digit, Numeric_Type=Decimal or Numeric_Type=Numeric.

()¶

Return if all characters in the string are printable or the string is empty, otherwise. Nonprintable characters are those characters defined in the Unicode character database as “Other” or “Separator”, excepting the ASCII space (0x20) which is considered printable. (Note that printable characters in this context are those which should not be escaped when is invoked on a string. It has no bearing on the handling of strings written to or .)

()¶

Return if there are only whitespace characters in the string and there is at least one character, otherwise.

A character is whitespace if in the Unicode character database (see ), either its general category is (“Separator, space”), or its bidirectional class is one of , , or .

()¶

Return if the string is a titlecased string and there is at least one character, for example uppercase characters may only follow uncased characters and lowercase characters only cased ones. Return otherwise.

()¶

Return if all cased characters 4 in the string are uppercase and there is at least one cased character, otherwise.

>>> 'BANANA'.isupper()True>>> 'banana'.isupper()False>>> 'baNana'.isupper()False>>> ' '.isupper()False
(iterable

Return a string which is the concatenation of the strings in iterable. A will be raised if there are any non-string values in iterable, including objects. The separator between elements is the string providing this method.

(width[, fillchar])¶

Return the string left justified in a string of length width. Padding is done using the specified fillchar (default is an ASCII space). The original string is returned if width is less than or equal to .

()¶

Return a copy of the string with all the cased characters 4 converted to lowercase.

The lowercasing algorithm used is described in section 3.13 of the Unicode Standard.

([chars])¶

Return a copy of the string with leading characters removed. The chars argument is a string specifying the set of characters to be removed. If omitted or , the chars argument defaults to removing whitespace. The chars argument is not a prefix; rather, all combinations of its values are stripped:

>>> ' spacious '.lstrip()'spacious '>>> 'www.example.com'.lstrip('cmowz.')'example.com'

See for a method that will remove a single prefix string rather than all of a set of characters. For example:

>>> 'Arthur: three!'.lstrip('Arthur: ')'ee!'>>> 'Arthur: three!'.removeprefix('Arthur: ')'three!'
static (x[, y[, z]])¶

This static method returns a translation table usable for .

If there is only one argument, it must be a dictionary mapping Unicode ordinals (integers) or characters (strings of length 1) to Unicode ordinals, strings (of arbitrary lengths) or . Character keys will then be converted to ordinals.

If there are two arguments, they must be strings of equal length, and in the resulting dictionary, each character in x will be mapped to the character at the same position in y. If there is a third argument, it must be a string, whose characters will be mapped to in the result.

(sep

Split the string at the first occurrence of sep, and return a 3-tuple containing the part before the separator, the separator itself, and the part after the separator. If the separator is not found, return a 3-tuple containing the string itself, followed by two empty strings.

(prefix, /

If the string starts with the prefix string, return . Otherwise, return a copy of the original string:

>>> 'TestHook'.removeprefix('Test')'Hook'>>> 'BaseTestCase'.removeprefix('Test')'BaseTestCase'
(suffix, /

If the string ends with the suffix string and that suffix is not empty, return . Otherwise, return a copy of the original string:

>>> 'MiscTests'.removesuffix('Tests')'Misc'>>> 'TmpDirMixin'.removesuffix('Tests')'TmpDirMixin'
(old, new[, count])¶

Return a copy of the string with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced.

(sub[, start[, end]])¶

Return the highest index in the string where substring sub is found, such that sub is contained within . Optional arguments start and end are interpreted as in slice notation. Return on failure.

(sub[, start[, end]])¶

Like but raises when the substring sub is not found.

(width[, fillchar])¶

Return the string right justified in a string of length width. Padding is done using the specified fillchar (default is an ASCII space). The original string is returned if width is less than or equal to .

(sep

Split the string at the last occurrence of sep, and return a 3-tuple containing the part before the separator, the separator itself, and the part after the separator. If the separator is not found, return a 3-tuple containing two empty strings, followed by the string itself.

(sep=None, maxsplit=- 1

Return a list of the words in the string, using sep as the delimiter string. If maxsplit is given, at most maxsplit splits are done, the rightmost ones. If sep is not specified or , any whitespace string is a separator. Except for splitting from the right, behaves like which is described in detail below.

([chars])¶

Return a copy of the string with trailing characters removed. The chars argument is a string specifying the set of characters to be removed. If omitted or , the chars

Sours: https://docs.python.org/3/library/stdtypes.html

JavaScript String replace()

❮ PreviousJavaScript String ReferenceNext ❯

Example

Return a string where "Microsoft" is replaced with "W3Schools":

let str = "Visit Microsoft!";
str.replace("Microsoft", "W3Schools");

Try it Yourself »

More "Try it Yourself" examples below.


Definition and Usage

The method searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced.

Note: If you are replacing a value (and not a regular expression), only the first instance of the value will be replaced. To replace all occurrences of a specified value, use the global (g) modifier (see "More Examples" below).

Read more about regular expressions in our RegExp Tutorial and our RegExp Object Reference.

does not change the original string.


Browser Support

is an ES1 feature (JavaScript 1999).

It is fully supported in all browsers:

ChromeIEEdgeFirefoxSafariOpera
YesYesYesYesYesYes

Syntax

string.replace(searchvalue, newvalue)

Parameter Values

ParameterDescription
searchvalueRequired. The value, or regular expression, that will be replaced by the new value
newvalueRequired. The value to replace the search value with


Technical Details

Return Value:A new String, where the specified value(s) has been replaced by the new value
JavaScript Version:ECMAScript 1

More Examples

Example

Perform a global replacement:

let str = "Mr Blue has a blue house and a blue car";
str.replace(/blue/g, "red");

Try it Yourself »

Example

Perform a global, case-insensitive replacement:

let str = "Mr Blue has a blue house and a blue car";
str.replace(/blue/gi, "red");

Try it Yourself »

Example

Using a function to return the replacement text:

let str = "Mr Blue has a blue house and a blue car";
str.replace(/blue|house|car/gi, function (x) {
  return x.toUpperCase();
});

Try it Yourself »

Related Pages

String Tutorial

String Methods

String Search


❮ PreviousJavaScript String ReferenceNext ❯


Sours: https://www.w3schools.com/jsref/jsref_replace.asp

Replace str

String.prototype.replace()

The method returns a new string with some or all matches of a replaced by a . The can be a string or a , and the can be a string or a function to be called for each match. If  is a string, only the first occurrence will be replaced.

The original string is left unchanged.

Syntax

Parameters

(pattern)

A object or literal. The match or matches are replaced with or the value returned by the specified .

A that is to be replaced by . It is treated as a literal string and is not interpreted as a regular expression. Only the first occurrence will be replaced.

(replacement)

The that replaces the substring specified by the specified or parameter. A number of special replacement patterns are supported; see the "Specifying a string as a parameter" section below.

If is an empty string, then the substring given by , or the matches for , are removed (rather then being replaced).

(replacement)

A function to be invoked to create the new substring to be used to replace the matches to the given or . The arguments supplied to this function are described in the "Specifying a function as a parameter" section below.

Return value

A new string, with some or all matches of a pattern replaced by a replacement.

Description

This method does not change the calling object. It returns a new string.

To perform a global search and replace, include the switch in the regular expression.

Specifying a string as a parameter

The replacement string can include the following special replacement patterns:

PatternInserts
Inserts a .
Inserts the matched substring.
Inserts the portion of the string that precedes the matched substring.
Inserts the portion of the string that follows the matched substring.
Where is a positive integer less than 100, inserts the th parenthesized submatch string, provided the first argument was a object. Note that this is -indexed. If a group is not present (e.g., if group is 3), it will be replaced as a literal (e.g., ).
Where is a capturing group name. If the group is not in the match, or not in the regular expression, or if a string was passed as the first argument to instead of a regular expression, this resolves to a literal (e.g., ). Only available in browser versions supporting named capturing groups.

Specifying a function as a parameter

You can specify a function as the second parameter. In this case, the function will be invoked after the match has been performed. The function's result (return value) will be used as the replacement string. (Note: The above-mentioned special replacement patterns do not apply in this case.)

Note that the function will be invoked multiple times for each full match to be replaced if the regular expression in the first parameter is global.

The arguments to the function are as follows:

Possible nameSupplied value
The matched substring. (Corresponds to above.)
The nth string found by a parenthesized capture group (including named capturing groups), provided the first argument to was a object. (Corresponds to , , etc. above.) For example, if , was given, is the match for , and  for .
The offset of the matched substring within the whole string being examined. (For example, if the whole string was , and the matched substring was , then this argument will be .)
The whole string being examined.
In browser versions supporting named capturing groups, will be an object whose keys are the used group names, and whose values are the matched portions ( if not matched).

(The exact number of arguments depends on whether the first argument is a object—and, if so, how many parenthesized submatches it specifies.)

The following example will set to :

Examples

Defining the regular expression in replace()

In the following example, the regular expression is defined in and includes the ignore case flag.

This logs .

Note: See this guide for more explanations about regular expressions.

Using global and ignore with replace()

Global replace can only be done with a regular expression. In the following example, the regular expression includes the global and ignore case flags which permits to replace each occurrence of in the string with .

This logs .

Switching words in a string

The following script switches the words in the string. For the replacement text, the script uses capturing groups and the and replacement patterns.

This logs .

Using an inline function that modifies the matched characters

In this example, all occurrences of capital letters in the string are converted to lower case, and a hyphen is inserted just before the match location. The important thing here is that additional operations are needed on the matched item before it is given back as a replacement.

The replacement function accepts the matched snippet as its parameter, and uses it to transform the case and concatenate the hyphen before returning.

Given , this returns .

Because we want to further transform the result of the match before the final substitution is made, we must use a function. This forces the evaluation of the match prior to the method. If we had tried to do this using the match without a function, the would have no effect.

This is because would first be evaluated as a string literal (resulting in the same ) before using the characters as a pattern.

Replacing a Fahrenheit degree with its Celsius equivalent

The following example replaces a Fahrenheit degree with its equivalent Celsius degree. The Fahrenheit degree should be a number ending with . The function returns the Celsius number ending with . For example, if the input number is , the function returns . If the number is , the function returns .

The regular expression checks for any number that ends with . The number of Fahrenheit degree is accessible to the function through its second parameter, . The function sets the Celsius number based on the Fahrenheit degree passed in a string to the function. then returns the Celsius number. This function approximates Perl's flag.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

Sours: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace

str_replace

(PHP 4, PHP 5, PHP 7, PHP 8)

str_replace — Replace all occurrences of the search string with the replacement string

Description

str_replace(
    array|string,
    array|string,
    string|array,
    int =
): string|array

If you don't need fancy replacing rules (like regular expressions), you should use this function instead of preg_replace().

Parameters

If and are arrays, then str_replace() takes a value from each array and uses them to search and replace on . If has fewer values than , then an empty string is used for the rest of replacement values. If is an array and is a string, then this replacement string is used for every value of . The converse would not make sense, though.

If or are arrays, their elements are processed first to last.

The value being searched for, otherwise known as the needle. An array may be used to designate multiple needles.

The replacement value that replaces found values. An array may be used to designate multiple replacements.

The string or array being searched and replaced on, otherwise known as the haystack.

If is an array, then the search and replace is performed with every entry of , and the return value is an array as well.

If passed, this will be set to the number of replacements performed.

Return Values

This function returns a string or an array with the replaced values.

Examples

Example #1 Basic str_replace() examples

Example #2 Examples of potential str_replace() gotchas

Notes

Note: This function is binary-safe.

Caution

Because str_replace() replaces left to right, it might replace a previously inserted value when doing multiple replacements. See also the examples in this document.

Note:

This function is case-sensitive. Use str_ireplace() for case-insensitive replace.

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To TopSours: https://www.php.net/manual/en/function.str-replace.php

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Python String replace()

The method replaces each matching occurrence of the old character/text in the string with the new character/text.

Example


replace() Syntax

It's syntax is:

str.replace(old, new [, count])

replace() Parameters

The method can take maximum of 3 parameters:

  • old - old substring you want to replace
  • new - new substring which will replace the old substring
  • count (optional) - the number of times you want to replace the substring with the substring

Note: If is not specified, the method replaces all occurrences of the substring with the substring.


replace() Return Value

The method returns a copy of the string where the substring is replaced with the substring. The original string is unchanged.

If the substring is not found, it returns the copy of the original string.


Example 1: Using replace()

Output


More Examples on String replace()

Output

Sours: https://www.programiz.com/python-programming/methods/string/replace


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