PHP preg_quote() function

The preg_last_error function is used to escape regular expression characters.

grammar

 string preg_quote ( string $str [, string $delimiter = NULL ] )

preg_quote() takes the parameter str and adds a backslash before each character in the regular expression syntax. This is typically used when you have some runtime strings that need to be matched as regular expressions.

Regular expression special characters are: . + * ? [ ^ ] $ ( ) { } = ! < > | : -

Parameter description:

$str: input string.

$delimiter: If the optional parameter delimiter is specified, it will also be escaped. This is typically used to escape delimiters used by the PCRE function. / is the most common delimiter.

return value

Returns the escaped string.

Example

Example 1

The execution result escapes the $ and / special characters as follows:

 Return$40 for a g3/400

Replace words in text with italics

The execution result is as follows:

 This book is <i>*very*</i> difficult to find.