preg_filter

Definition and usage

preg_filter() function returns a string or array of strings where the pattern match has been replaced by the replacement string.

If the input is an array, the function returns an array. If the input is a string, this function returns a string.

This function is similar to preg_replace() , but with one difference: when no content matching the pattern is found in the input string, the string will not be used for the return value. In this case, if the input is a string instead of an array, the function returns null.

The replacement string may contain a backward reference in the form of \n or n , where n is the index of the group in the pattern. In the returned string, instances of \n and n will be replaced by the substring that matches the group, or if \0 or $0 is used, they will be replaced by the entire expression.

Example

In the string list, enclose the numbers in brackets:

 <?php
$input = [  
  "It's 5 o'clock now" ,  
  "40 days" ,  
  "There are no numbers here" ,  
  "In 2000"  
] ;  
  
$result = preg_filter ( '/[0-9]+/' , '($0)' , $input ) ;  
print_r ( $result ) ;  
?>

Try it yourself

grammar

 preg_filter ( pattern , replacement , input , limit , count )

Parameter value