PHP RegEx

Regular Expressions.

PHP Regular Expressions

A regular expression is a sequence of characters that forms a search pattern. When you search for data in a text, you can use this search pattern to describe what you are searching for.

Regular expressions can be used to perform all types of text search and text replace operations.

Common RegEx Functions

preg_match() - Returns 1 if the pattern was found in the string and 0 if not
preg_match_all() - Returns the number of times the pattern was found in the string
preg_replace() - Returns a new string where matched patterns have been replaced with another string

RegEx Modifiers

i - Performs a case-insensitive search
m - Performs a multiline search
u - Enables correct matching of UTF-8 encoded patterns