InterestingArrayFunctions.php

<?php

$elements = array(1, 2, 3);

// array_map
// (PHP 4 >= 4.0.6, PHP 5)
$mappedElements = array_map(
  function($element) {
  	return 2 * $element; 
  }, 
  $elements
);

var_dump($mappedElements);

print("\n");


// array_walk
// (PHP 4, PHP 5)
$mappedElements2 = array_walk(
  $elements,
  function($element) {
  	echo 2 * $element . "\n"; 
  }
);

var_dump($mappedElements2); // true or false


// array_filter
// (PHP 4 >= 4.0.6, PHP 5)
$oddNumbers = array_filter(
  $elements, 
  function ($element) {
    return $element % 2 == 1;
  }
);

var_dump($oddNumbers);

// array_reduce
// (PHP 4 >= 4.0.5, PHP 5)
$mult = array_reduce(
  $elements, 
  function ($acc, $element) {
    return $acc *= $element;
  },
  1
);

var_dump($mult);

// array_any 
// (not in PHP yet)
function array_any($array, $predicate) {
  for ($i = 0; $i < sizeof($array); $i++) {
    $element = $array[$i];
    if ($predicate($element)) {
      return true;
    }
  }
  return false;
}

var_dump(
  array_any(
    $elements, 
    function($number) {
      return $number % 2 === 1;
    }
  )
);

var_dump(
  array_any(
    $elements, 
    function($number) {
      return $number > 20;
    }
  )
);