The "array_reduce()" function is used to send the values in an array to a user defined function and return a string.

    array_reduce(array,function,initial value)

In the above syntax "array" specifies the array from which the values are passed to the function, even one can specify the initial value to be passed.

    <?php
    function funct1($x1,$x2) 
      {
       return $x1 . "-" . $x2;
      }
    function funct2 ($y1,$y2)
      {
       return $y1+$y2
      }
    $a=array("Orange","Guava","Apple");
    $b=array(5,10,20); 
    print_r(array_reduce($a,"funct1",6));
    print "<br>";
    print_r(array_reduce($b,"funct2",6));
    ?>

    6-Orange-Guava-Apple
    41 

In the above example "funct1" returns a string with the intial value 6 added to the existing array, in the second "funct2" it returns the sum of the numbers of the array "$b".