This listing of the differences between PHP4 and PHP 5 is is probably something that is quite common, but it is always worth a review. PHP5 is a lot different than PHP4 with the main differences being in how it …

Differences between PHP4 and PHP5 Read More »

PHP’s preg_split() function enables you to break a string apart basing on something more complicated than a literal sequence of characters. When it’s necessary to split a string with a dynamic expression rather than a fixed one, this function comes …

Regular Expressions Part 4 – Array Processing Read More »

Replacing Patterns In the examples in Part 2, we have searched for patterns in a string, leaving the search string untouched. The preg_replace() function looks for substrings that match a pattern and then replaces them with new text. preg_replace() takes …

Regular Expressions Part 3 – Replacing Patterns Read More »

Matching Patterns The preg_match() function performs Perl-style pattern matching on a string. preg_match() takes two basic and three optional parameters. These parameters are, in order, a regular expression string, a source string, an array variable which stores matches, a flag …

Regular Expressions Part 2 – Matching Patterns Read More »

In programming you quite often want to test a string for the occurrence of a character or group of characters. This is particularly true for such things as data validation on form input boxes. Regular expressions provide a pattern matching …

Regular Expressions Part 1 – Introduction Read More »

To help counter SQL injections you need to make sure that entered values use minimum character types as possible. So you restrict usernames to just a-z and 0-9 characters. To test for these, use something like : //—————————————————— /** * …

Use regular expressions to validate PHP inputs Read More »