explode(separator,string,limit)
<?php
$string = "This is a string for testing explode function.";
print_r (explode(" ",$str));
?>
Array ( [0] => This [1] => is [2] => a [3] => string [4] => for [5] => testing. )
<?php
$array_test = array('This','is','for','testing');
echo implode(" ",$array_test)."<br>"; // This is for testing
echo implode("+",$array_test)."<br>"; // This+is+for+testing
echo implode("-",$array_test)."<br>"; // This-is-for-testing
?>