Detailed explanation of several string replacement functions in php_PHP tutorial

There are several character replacement functions in PHP: str_replace, substr_replace, preg_replace, preg_split, str_split and other functions. Let me summarize and introduce them to you. ​

1. str_replace(find,replace,string,count)

Function: The str_replace() function uses a string to replace other characters in the string.

Parameter Description
find required. Specifies the value to be found.
replace required. Specifies the value to replace the value in find.
string required. Specifies the string to be searched for.
count optional. A variable counting the number of substitutions.

Example

In this example we will demonstrate the str_replace() function with an array and count variable:

The code is as follows

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代码如下	复制代码
$arr = array("blue","red","green","yellow"); print_r(str_replace("red","pink",$arr,$i)); echo "Replacements: $i"; ?>输出： Array ( [0] => blue [1] => pink [2] => green [3] => yellow ) Replacements: 1

$arr = array("blue","red","green","yellow");

print_r(str_replace("red","pink",$arr,$i));

echo "Replacements: $i";

?>Output: Array

(

[0] => blue

[1] => pink

[2] => green
[3] => yellow
)
Replacements: 1

Added: If count is specified, its value will be set to the number of times replacement occurs.


2. substr_replace(string,replacement,start,length)

Function: The substr_replace() function replaces part of a string with another string.

Parameter Description
string required. Specifies the string to check.

replacement required. Specifies the string to be inserted.

start is required. Specifies where in the string to begin replacement.

代码如下	复制代码
echo substr_replace("Hello world","earth",6); ?> 输出： Hello earth

■Positive number - start replacing at start offset

■Negative numbers - replace
starting at the start offset from the end of the string ■0 - Start replacing at the first character in the string charlist Optional. Specifies how many characters to replace.

■Positive number - the length of the string to be replaced

■Negative number - the number of characters to be replaced starting from the end of the string

■0 - insert instead of replace


Example

The code is as follows

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echo substr_replace("Hello world","earth",6); ?>

Output:

代码如下	复制代码
$string = 'April 15, 2003'; $pattern = '/(w+) (d+), (d+)/i'; $replacement = '1,'; echo preg_replace($pattern, $replacement, $string); ?>

Hello earth

3. preg_replace (pattern, replacement, subject, limit = -1, $count) Function: Perform a regular expression search and replace Parameter Description pattern required. The pattern to search for. replacement required. String or array to use for replacement. subject required. String or array to be replaced. limit the number of replacements. -1 is unlimited count The number of times the replacement has been completed, variable Example #1 Use a back reference to follow the original text of the value

The code is as follows	Copy code
$string = 'April 15, 2003'; $pattern = '/(w+) (d+), (d+)/i'; $replacement = '${1}1,$3'; echo preg_replace($pattern, $replacement, $string); ?>

The above routine will output:

April1,2003

Example #2 Using index-based arrays in preg_replace()

The code is as follows

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$string = 'The quick brown fox jumped over the lazy dog.';

代码如下	复制代码
$string = 'The quick brown fox jumped over the lazy dog.'; $patterns = array(); $patterns[0] = '/quick/'; $patterns[1] = '/brown/'; $patterns[2] = '/fox/'; $replacements = array(); $replacements[2] = 'bear'; $replacements[1] = 'black'; $replacements[0] = 'slow'; echo preg_replace($patterns, $replacements, $string); ?>

$patterns = array();

$patterns[0] = '/quick/';

$patterns[1] = '/brown/';

$patterns[2] = '/fox/';

$replacements = array();

$replacements[2] = 'bear'; $replacements[1] = 'black'; $replacements[0] = 'slow';

echo preg_replace($patterns, $replacements, $string);

?>

The above routine will output:

The bear black slow jumped over the lazy dog.


4. preg_split (pattern, subject, limit = -1, flag)

Function: Split strings through regular expressions

代码如下	复制代码
// split the phrase by any number of commas or space characters, // which include " ", r, t, n and f $keywords = preg_split ("/[s,]+/", "hypertext language, programming"); ?>

Parameter Description

pattern required. The pattern to search for.

replacement required. String or array to use for replacement.

代码如下	复制代码
$str = 'string'; $chars = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY); print_r($chars); ?>

subject required. The string that needs to be replaced.

limit The string to be split is at most limit.

flag mode

代码如下	复制代码
$str = 'hypertext language programming'; $chars = preg_split('/ /', $str, -1, PREG_SPLIT_OFFSET_CAPTURE); print_r($chars); ?>

Example 1672. preg_split() Example: Get the components of the search string

The code is as follows	Copy code
// split the phrase by any number of commas or space characters, // which include " ", r, t, n and f $keywords = preg_split ("/[s,]+/", "hypertext language, programming"); ?>

Example 1673. Split string into characters

The code is as follows	Copy code
$str = 'string'; $chars = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY); print_r($chars); ?>

Example 1674. Split a string into matches and their offsets

The code is as follows	Copy code
$str = 'hypertext language programming'; $chars = preg_split('/ /', $str, -1, PREG_SPLIT_OFFSET_CAPTURE); print_r($chars); ?>

This example will output:

Array

( [0] => Array (

[0] => hypertext

[1] => 0

)

[1] => Array
(

[0] => language

[1] => 10

)

代码如下	复制代码
print_r(str_split("Hello")); ?>

[2] => Array ( [0] => programming [1] => 19 ) ) 5. str_split (subject, length) Function: Split the string into arrays Parameter Description subject string. length The length of each segment. Example 1

The code is as follows	Copy code
print_r(str_split("Hello")); ?>

Output:

Array
(
[0] => H
[1] => e
[2] => l
[3] => l
[4] => o
)

Example 2

The code is as follows

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print_r(str_split("Hello",3));

代码如下	复制代码
print_r(str_split("Hello",3)); ?>

?>

Output:

Array
(
[0] => Hel
[1] => lo
)

http://www.bkjia.com/PHPjc/445631.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445631.htmlTechArticleThere are several character replacement functions in php such as str_replace, substr_replace, preg_replace, preg_split, str_split and other functions. Let me give you a summary and introduction below. 1. str_repla...