PHP Cookbook

1.11. Taking Strings Apart

Problem

You need to break a string into pieces. For example, you want to access each line that a user enters in a <textarea> form field.

Solution

Use explode( ) if what separates the pieces is a constant string:

$words = explode(' ','My sentence is not very complicated');

Use split( ) or preg_split( ) if you need a POSIX or Perl regular expression to describe the separator:

$words = split(' +','This sentence  has  some extra whitespace  in it.');
$words = preg_split('/\d\. /','my day: 1. get up 2. get dressed 3. eat toast');
$lines = preg_split('/[\n\r]+/',$_REQUEST['textarea']);

Use spliti( ) or the /i flag to preg_split( ) for case-insensitive separator matching:

$words = spliti(' x ','31 inches x 22 inches X 9 inches');
$words = preg_split('/ x /i','31 inches x 22 inches X 9 inches');

Discussion

The simplest solution of the bunch is explode( ). Pass it your separator string, the string to be separated, and an optional limit on how many elements should be returned:

$dwarves = 'dopey,sleepy,happy,grumpy,sneezy,bashful,doc';
$dwarf_array = explode(',',$dwarves);

Now $dwarf_array is a seven element array:

print_r($dwarf_array);
Array
               (
                   [0] => dopey
                   [1] => sleepy
                   [2] => happy
                   [3] => grumpy
                   [4] => sneezy
                   [5] => bashful
                   [6] => doc
               )

If the specified limit is less than the number of possible chunks, the last chunk contains the remainder:

$dwarf_array = explode(',',$dwarves,5);
print_r($dwarf_array);
Array
               (
                   [0] => dopey
                   [1] => sleepy
                   [2] => happy
                   [3] => grumpy
                   [4] ...