Remove extra spaces from string in php

Removing the space into string using php.this problem facing many time by the php coder. i am trying to solve this problem here.remove extra space from string using php,remove space in php,how to hide extra space from string using php.

 Type 1 :  trim( ) Function

This function only remove space before and after the string
<?php
         $str="   This is only for test     ";
         echo trim($str);
?>
// output
        This is only for test


Type 2 :  preg_replace( ) Function

This Function remove space between the string

<?php 

     $str="This    is    only   for    test"; 

     $str = preg_replace("/\s+/"," ",$str);
        echo $str;

?>

//output

     This is only for test

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