Perl-Compatible Regular Expressions Part 1 Chapter 14 Perl-Compatible Regular Expressions Part 1

preg_match The match function is 1st argument is the pattern int preg_match(string $pattern, string $str ) 1st argument is the pattern 2nd argument is the subject string Returns number of matches found: 1 (true) if there is a match – it stops at the first match found! 0 (false) otherwise

pcre.php Script 14.1 on page 435 http://csweb.hh.nku.edu/csc301/frank/ch14/pcre.php ch14\pcre.php

Character Classes [A-Z] uppercase letter [a-z] lowercase letter [0-9] digit {5} exactly five {3,} three or more {1,4} one to four

Metacharacters ^ beginning of string $ end of string | or

Regular Expression Username – 5 to 10 lowercase letters? $pattern = '/^[a-z]{5,10}$/'; if (!preg_match($pattern, $username)) { echo "<p>$username is invalid.</p>"; }

Regular Expressions Social Security Number 123-45-6789 $pattern = '/^[0-9]{3}-[0-9]{2}-[0-9]{4}$/'; if (!preg_match($pattern, $ssn)) { echo "<p>$ssn is invalid.</p>"; }

Character classes \d any digit [0-9] \D any non-digit [^0-9] \w Any letter, number, or underscore [A-Za-z0-9_] \W Anything that is not a letter, number, or underscore [^A-Za-z0-9_]

Character classes \s whitespace (space, tab, new line, etc.) [\f\r\t\n\v] \S Any non-whitespace [^\f\r\t\n\v]

Regular Expressions Social Security Number 123-45-6789 $pattern = '/^\d{3}-\d{2}-\d{4}$/'; if (!preg_match($pattern, $ssn)) { echo "<p>$ssn is invalid.</p>"; }

Metacharacters [0-9]* * = zero or more [A-Z]+ + = one or more . . = match any character ([A-Z]\. )? ? = either zero or one

Regular Expressions Last name: Frank $pattern = '/^[A-Z][a-z]+$/'; if (!preg_match($pattern, $last)) { echo "<p>$last is invalid.</p>"; }

Regular Expressions Name: Charles Frank or Charles E. Frank $pattern = '/^[A-Z][a-z]+ ([A-Z]\. )?[A-Z][a-z]+ $/'; if (!preg_match($pattern, $name)) { echo "<p>$name is invalid.</p>"; }

Zip Code Page 444 /^\d{5}(-\d{4})?$/

Email Address Page 445 /^[\w.]+@[\w.-]+\.[A-Za-z]{2,6}$/