Home >Backend Development >PHP Tutorial >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 | Copy code | ||||
print_r(str_replace("red","pink",$arr,$i)); echo "Replacements: $i";?>Output: Array ([0] => blue [1] => pink
[2] => green |
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.
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 |
■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 | Copy code | ||||
echo substr_replace("Hello world","earth",6); ?> Output:
|
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 | Copy code | ||||
$string = 'The quick brown fox jumped over the lazy dog.';
$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 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, |
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'; |
limit The string to be split is at most limit.
flag mode代码如下 | 复制代码 |
$str = 'hypertext language programming'; |
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, |
The code is as follows | Copy code |
$str = 'string';
$chars = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY); |
The code is as follows | Copy code |
$str = 'hypertext language programming'; |
Array
( [0] => Array (
[0] => hypertext[1] => 0
)
[1] => Array
(
[1] => 10
)代码如下 | 复制代码 |
print_r(str_split("Hello")); ?> |
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 | Copy code | ||||
print_r(str_split("Hello",3));
|
Output:
Array
(
[0] => Hel
[1] => lo
)