How to replace a certain character to be empty in a php string

Two methods for replacing a certain character with a null character in a php string: 1. Use the str_replace() function to replace the specified character with a null character. You only need to set the first parameter to the specified character, and the second The parameter is set to a null character, the syntax "str_replace("specified character","", $str)"; 2. Use the preg_replace() function with a regular expression to match the specified character and replace it with the null character, the syntax "preg_replace(' /Specify character/',"",$str)".

The operating environment of this tutorial: windows7 system, PHP8 version, DELL G3 computer

If you want to replace a certain character in the php string, you can Use the following two functions:

• Use str_replace() function

• Use preg_replace() function

Method 1: Use the str_replace() function to replace a certain character with an empty space

The str_replace() function replaces some characters in the string (case sensitive) .

str_replace(find,replace,string,count)

Parameters	Description
find	Required . Specifies the value to look for.
replace	Required. Specifies a value that replaces the value in find.
string	Required. Specifies the string to be searched for.
count	Optional. A variable counting the number of substitutions.

• Return value: Returns a string or array with the replacement value.
  

You only need to set the first parameter find to the specified character, and the second parameter replace to the empty character ''.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str= &#39;abcd123abcd&#39;;
echo "原字符串：".$str."<br>";
$newStr = str_replace("c", "", $str); 
echo "替换后：".$newStr;
?>

As you can see, replacing a character with a blank value means deleting the specified character.

Note: The str_replace() function must follow the following rules

• If the searched string is an array, then it will return an array.

• If the searched string is an array, then it will find and replace each element in the array.

• If an array needs to be searched and replaced at the same time, and the elements to be replaced are less than the number of found elements, the excess elements will be replaced with empty strings .

• If you search an array and replace only one string, the replacement string will work for all found values.

Method 2: Use the preg_replace() function to replace a certain character with an empty character

Use the preg_replace() function with the regular expression "/specified character/" to match the specified character and replace it with the empty character ''.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str= &#39;HELLO&#39;;
echo $str."<br>";
$newStr = preg_replace(&#39;/L/&#39;, "", $str); 
echo $newStr;
?>

Description: The

preg_replace function performs a regular expression search and replacement.

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

Search for the part matching pattern in subject and replace it with replacement.

Parameter description:

• $pattern: The pattern to be searched, which can be a string or a string array.

• $replacement: String or array of strings used for replacement.

• $subject: The target string or string array to be searched and replaced.

• $limit: Optional, the maximum number of substitutions for each subject string per pattern. The default is -1 (no limit).

• $count: Optional, the number of times the replacement is performed.

Return value

• If subject is an array, preg_replace() returns an array, otherwise it returns a string.

• If a match is found, the replaced subject is returned, otherwise the unchanged subject is returned. If an error occurs, NULL is returned.

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