How to split every two words in a sentence?

[etrader]

In a string containing a simple sentence as

$str="word1 word2 word3 word4 word5"

I want to split every two words. Actually, performing explode() for every other 'space' (not all of them). To create

$array[0]="word1 word2";
$array[1]="word3 word4";
$array[2]="word5";

 

Any idea?

[HDFilmMaker2112]

There's about 5 different ways to do it here:

http://stackoverflow.com/questions/857441/php-explode-over-every-other-word-with-a-twist

[etrader]

Nice reference!

I like when facing such creative ideas to handle an issue in php