Perl has long been considered one of the most powerful parsing languages ever written,and it provides a comprehensive regular expression language that can be used to search and replace even the most complicated of string patterns. The developers of PHP felt that instead of reinventing the regular expression wheel, so to speak, they should make the famed Perl regular expression syntax available to PHP users .
Perl’s regular expression syntax is actually a derivation of the POSIX implementation, resulting in considerable similarities between the two. You can use any of the quantifiers introduced in the previous POSIX section. The remainder of this section is devoted to a brief introduction of Perl regular expression syntax. Let’s start with a simple example of a Perl-based regular expression:
Notice that the string food is enclosed between two forward slashes. Just as with POSIX regular expressions, you can build a more complex string through the use of quantifiers:
This will match fo followed by one or more characters. Some potential matches include food, fool, and fo4. Here is another example of using a quantifier:
This matches f followed by two to four occurrences of o. Some potential matches include fool, fooool, and foosball
Perl’s regular expression syntax is actually a derivation of the POSIX implementation, resulting in considerable similarities between the two. You can use any of the quantifiers introduced in the previous POSIX section. The remainder of this section is devoted to a brief introduction of Perl regular expression syntax. Let’s start with a simple example of a Perl-based regular expression:
Notice that the string food is enclosed between two forward slashes. Just as with POSIX regular expressions, you can build a more complex string through the use of quantifiers:
This will match fo followed by one or more characters. Some potential matches include food, fool, and fo4. Here is another example of using a quantifier:
This matches f followed by two to four occurrences of o. Some potential matches include fool, fooool, and foosball
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