PHP and Regular Expressions 101 Page 2

PHP has six functions that work with regular expressions. They all take a regular expression string
as their first argument, and are shown below:

• ereg: The most common regular expression function, ereg allows us
  to search a string for matches of a regular expression.
• ereg_replace: Allows us to search a string for a regular expression and replace
  any occurrence of that expression with a new string.
• eregi: Performs exactly the same matching as ereg, but is case
  insensitive.
• eregi_replace: Performs exactly the same search-replace functionality as
  ereg_replace, but is case insensitive.
• split: Allows us to search a string for a regular expression and returns the
  matches as an array of strings.
• spliti: Case insensitive version of the split function

This article originally appeared on WebReference.com.