PHP/Data Structure/array map

Applying Functions to Array Elements Using array_map()

 
<?php
  function array_display($array, $pre=FALSE)
  {
    $tag = $pre ? "pre" : "p";
    printf("<%s>%s</%s>\n", $tag, var_export($array, TRUE), $tag);
  }
  function calc_sqrt($num)
  {
    $i = $num < 0 ? "i" : "";
    return sqrt( abs($num) ) . $i;
  }
  $values = array(3, 8, -3, 0, 14, -4);
  $roots = array_map("calc_sqrt", $values);
  print "<p>Values:</p>";
  array_display($values, TRUE);
  print "<p>Square roots:</p>";
  array_display($roots, TRUE);
?>

Using array_map() and array_walk() together

 
<?php
  function array_display($array, $pre=FALSE)
  {
    $tag = $pre ? "pre" : "p";
    printf("<%s>%s</%s>\n", $tag, var_export($array, TRUE), $tag);
  }
  function get_pay($emp, $hr, $rt)
  {
    return sprintf("%s worked %.2f hours, and grossed $%.2f",
                   $emp, $hr, $rt * $hr);
  }
  function display_pd_emp(&$el)
  {
    printf("<p>%s.</p>\n", $el);
  }
  $employees = array("A", "B", "C", "D", "N");
                     
  $hours = array(35.2, 37.4, 41.3, 28.8, 38.5);
  $rates = array(12.5, 12.5, 13.75, 9.85, 11.6);
  $paid_emps = array_map("get_pay", $employees, $hours, $rates);
  array_walk($paid_emps, "display_pd_emp");
  array_display($paid_emps, TRUE);
?>

Using the array_map() Function

 
<?php
    function my_callback($var) {
        echo "Value: $var<BR>";
        return strtoupper($var);
    }
    $myarray = array("hello", "this", "is", "a", "callback!");
    $newarray = array_map("my_callback", $myarray);
    echo "<PRE>";
    print_r($newarray);
    echo "</PRE>";
?>