Advanced String Processing – How Regular Are Your Expressions – The ABC’s of PHP – Part 9

“Huh, Regular What?

“Put simply, a regular expression is a string in it’s own right,
but one that has a special meaning. In some ways it’s like a little
mini program that tells the regexp engine what to look for and how
to find it.

“Look at the first line of my opening paragraph above. If you
wanted to look for that “Hello hello hello” and treat it as a
spelling error to correct how are you going to find it?

“Well you could use

if($text == “Hello hello hello”)

“or you might use the text function “str_replace”:

str_replace(“Hello hello hello”,”Hello”);

“and they would work fine, but what if we now made the phrase
“Hello hello hullo”? hmmm, it looks like we now don’t have a match.
This is where the power of regular expressions comes to the
rescue.”

Complete
Story