Combine arrays in PHP [duplicate]

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Possible开发者_运维知识库 Duplicate:

Transposing multidimensional arrays in PHP

I have three arrays:

$a = (a1, a2, a3);
$b = (b1, b2, b3);
$c = (c1, c2, c3);

I want to combine these arrays to create:

$newa = (a1, b1, c1);
$newb = (a2, b2, c2);
$newc = (a3, b3, c3);

---

function transpose(){
    $array = func_get_args();
    array_unshift($array, null);
    return call_user_func_array('array_map', $array);
}

$a = array('a1', 'a2', 'a3');
$b = array('b1', 'b2', 'b3');
$c = array('c1', 'c2', 'c3');

list($newa, $newb, $newc) = transpose($a,$b,$c);

var_dump($newa, $newb, $newc);

Transpose function from here, and slightly modified by me.

---

I changed things a little. I didn't use $newA, #newB, $newC, but used a $m array instead.

    $a = array( "a1", "a2", "a3");
    $b = array( "b1", "b2", "b3");
    $c = array( "c1", "c2", "c3");

$count = count($a);
$i = 0;
$m = array();
for($i;$i < $count; $i++) {
        $m[] = array( $a[$i], $b[$i], $c[$i]);
}

print_r($m);

Outputs:

Array
(
    [0] => Array
        (
            [0] => a1
            [1] => b1
            [2] => c1
        )

    [1] => Array
        (
            [0] => a2
            [1] => b2
            [2] => c2
        )

    [2] => Array
        (
            [0] => a3
            [1] => b3
            [2] => c3
        )

)

---

How about this...

<?php

$arr1 = array(1, 2, 3);
$arr2 = array(1, 2, 3);
$arr3 = array(1, 2, 3);

function array_divide() {
    $ret = array();
    foreach (func_get_args() as $array) {
        foreach ($array as $key=>$value) {
            $ret[$key][] = $value;
        }
    }
    return $ret;
}

list($new1, $new2, $new3) = array_divide($arr1, $arr2, $arr3);
var_dump($new1);

Obviously the function can only return one value, so you'll need list if you want to get multiple values out of it.

---

Here's my bid. Tried to make it as flexible as possible:

function array_rotate(){
  $args = func_get_args();
  $argc = func_num_args();

  // check if all items are arrays and also get the
  // length of the longest array
  $maxCount = 0;
  foreach ($args as $arg){
    if (!is_array($arg))
      throw new ArgumentException("array_rotate: All arguments must be arrays");
    $_count = count($arg);
    if ($_count > $maxCount)
      $maxCount = $_count;
  }

  // setup the returned result
  $result = array_fill(0, $argc, array());

  // iterate over all items
  for ($v = 0; $v < $argc; $v++){
    for ($h = 0; $h < $maxCount; $h++){
      $result[$h][$v] = isset($args[$v][$h]) ? $args[$v][$h] : null;
    }
  }

  return $result;
}

And example usage:

$newAry = array_rotate(
  array('a1','a2','a3'),
  array('b1','b2','b3'),
  array('c1','c2','c3')
);

// above yields:
Array
(
    [0] => Array
        (
            [0] => a1
            [1] => b1
            [2] => c1
        )

    [1] => Array
        (
            [0] => a2
            [1] => b2
            [2] => c2
        )

    [2] => Array
        (
            [0] => a3
            [1] => b3
            [2] => c3
        )

)

And in cases of uneven arrays, null is returned:

print_r(array_rotate(
  array('a1','a2'),
  array('b1','b2','b3','b4'),
  array('c1','c2','c3')
));

// above yields:
Array
(
    [0] => Array
        (
            [0] => a1
            [1] => b1
            [2] => c1
        )

    [1] => Array
        (
            [0] => a2
            [1] => b2
            [2] => c2
        )

    [2] => Array
        (
            [0] => 
            [1] => b3
            [2] => c3
        )

    [3] => Array
        (
            [0] => 
            [1] => b4
            [2] => 
        )
)