ZEND PHP 5 Certification STUDY GUIDE

Strings And Patterns ” 91
. Match any character
ˆ Match the start of the string
$ Match the end of the string
\s Match any whitespace character
\d Match any digit
\w Match any “word” character
Metacharacters can also be expressed using grouping expressions. For example, a
series of valid alternatives for a character can be provided by using square brackets:
/ab[cd]e/
The expression above will match both abce and abde. You can also use other
metacharacters, and provide ranges of valid characters inside a grouping expression:
/ab[c-e\d]/
This will match abc, abd, abe and any combination of ab followed by a digit.
Quantifiers
A quantifier allows you to specify the number of times a particular character or
metacharacter can appear in a matched string. There are four types of quantifiers:
* The character can appear zero or more times
+ The character can appear one or more times
? The character can appear zero or one times
{n,m} The character can appear at least n times, and no more than m.
Either parameter can be omitted to indicated a minimum limit
with no maximum, or a maximum limit without a minimum, but
not both.
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)
Thus, for example, the expression ab?c matches both ac and abc, while ab{1,3}c
matches abc, abbc and abbbc.