在PHP中转置多维数组

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

或者如果您使用的是PHP5.6或更高版本:

function transpose($array) {
    return array_map(null, ...$array);
}

有两个回路。

function flipDiagonally($arr) {
    $out = array();
    foreach ($arr as $key => $subarr) {
        foreach ($subarr as $subkey => $subvalue) {
            $out[$subkey][$key] = $subvalue;
        }
    }
    return $out;
}

我想你指的是阵列 transpose

这里有一个函数可以帮你实现 (source) :

function array_transpose($array, $selectKey = false) {
    if (!is_array($array)) return false;
    $return = array();
    foreach($array as $key => $value) {
        if (!is_array($value)) return $array;
        if ($selectKey) {
            if (isset($value[$selectKey])) $return[] = $value[$selectKey];
        } else {
            foreach ($value as $key2 => $value2) {
                $return[$key2][$key] = $value2;
            }
        }
    }
    return $return;
} 

function transpose($array, &$out, $indices = array())
{
    if (is_array($array))
    {
        foreach ($array as $key => $val)
        {
            //push onto the stack of indices
            $temp = $indices;
            $temp[] = $key;
            transpose($val, $out, $temp);
        }
    }
    else
    {
        //go through the stack in reverse - make the new array
        $ref = &$out;
        foreach (array_reverse($indices) as $idx)
            $ref = &$ref[$idx];
        $ref = $array;
    }
}

$foo[1][2][3][3][3] = 'a';
$foo[4][5][6][5][5] = 'b';

$out = array();
transpose($foo, $out);

echo $out[3][3][3][2][1] . ' ' . $out[5][5][6][5][4];

基本上,它递归地遍历数组,将数组中的当前指示符累加起来。

我需要一个支持关联数组的转置函数:

    $matrix = [
        ['one' => 1, 'two' => 2],
        ['one' => 11, 'two' => 22],
        ['one' => 111, 'two' => 222],
    ];

    $result = \array_transpose($matrix);

    $trans = [
        'one' => [1, 11, 111],
        'two' => [2, 22, 222],
    ];

回去的路上:

    $matrix = [
        'one' => [1, 11, 111],
        'two' => [2, 22, 222],
    ];

    $result = \array_transpose($matrix);

    $trans = [
        ['one' => 1, 'two' => 2],
        ['one' => 11, 'two' => 22],
        ['one' => 111, 'two' => 222],
    ];

array_unshift 诡计不起作用 array_map ...

所以我编了一个 array_map_join_array 处理记录键关联的函数:

/**
 * Similar to array_map() but tries to join values on intern keys.
 * @param callable $callback takes 2 args, the intern key and the list of associated values keyed by array (extern) keys.
 * @param array $arrays the list of arrays to map keyed by extern keys NB like call_user_func_array()
 * @return array
 */
function array_map_join_array(callable $callback, array $arrays)
{
    $keys = [];
    // try to list all intern keys
    array_walk($arrays, function ($array) use (&$keys) {
        $keys = array_merge($keys, array_keys($array));
    });
    $keys = array_unique($keys);
    $res = [];
    // for each intern key
    foreach ($keys as $key) {
        $items = [];
        // walk through each array
        array_walk($arrays, function ($array, $arrKey) use ($key, &$items) {
            if (isset($array[$key])) {
                // stack/transpose existing value for intern key with the array (extern) key
                $items[$arrKey] = $array[$key];
            } else {
                // or stack a null value with the array (extern) key
                $items[$arrKey] = null;
            }
        });
        // call the callback with intern key and all the associated values keyed with array (extern) keys
        $res[$key] = call_user_func($callback, $key, $items);
    }
    return $res;
}

array_transpose

function array_transpose(array $matrix)
{
    return \array_map_join_array(function ($key, $items) {
        return $items;
    }, $matrix);
}

如果您试图用splat操作符解压OP的示例数据( ... ),您将生成:

Proof

要克服此错误,请调用 array_values() 在解包之前索引一级键。

var_export(array_map(null, ...array_values($foo)));

输出:

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',
  ),
)

使用这种技术进行转置的另一个特点/惊喜是 null 当子阵列的大小不同时,将生成元素…但可能不是您预期的位置。

根据如下示例数据:

$foo = array(
    'a' => array(
       1 => 'a1',
       2 => 'a2'
    ),
    'b' => array(
       1 => 'b1',
       3 => 'b3' 
    ),
    'c' => array(
       1 => 'c1',
       2 => 'c2',
       3 => 'c3' 
    )
);

输出为:

array (
  0 => 
  array (
    0 => 'a1',
    1 => 'b1',
    2 => 'c1',
  ),
  1 => 
  array (
    0 => 'a2',
    1 => 'b3',
    2 => 'c2',
  ),
  2 => 
  array (
    0 => NULL,
    1 => NULL,
    2 => 'c3',
  ),
)

请注意该功能所表现出的级别小心(与从飞机腹部取出行李的行李处理人员相当)。没有注意到原始子数组值的id(如果 1 , 2 3 是 x , y ,& z

foreach() 无效的 元素,在大多数实现中,它访问所有子数组值的能力取决于第一个子数组的长度。

$foo = array(
    'a' => array(
       1 => 'a1',
       2 => 'a2'
    ),
    'b' => array(
       1 => 'b1',
    ),
    'c' => array(
       1 => 'c1',
       2 => 'c2',
       3 => 'c3' 
    )
);

foreach (current($foo) as $column => $not_used) {
    $result[] = array_column($foo, $column);
}
var_export($result);

输出:

array (
  0 => 
  array (
    0 => 'a1',
    1 => 'b1',
    2 => 'c1',
  ),
  1 => 
  array (
    0 => 'a2',
    1 => 'c2',
  ),
)

如上所示,如果要确保从输入数组中提取了所有数据,就必须编写加法逻辑,将所有唯一的列id传递给foreach循环。

an uglier, more verbose functional transposer that copped some criticism

我也遇到了同样的问题。下面是我想到的:

function array_transpose(array $arr)
{
    $keys    = array_keys($arr);
    $sum     = array_values(array_map('count', $arr));

    $transposed = array();

    for ($i = 0; $i < max($sum); $i ++)
    {
        $item = array();
        foreach ($keys as $key)
        {
            $item[$key] = array_key_exists($i, $arr[$key]) ? $arr[$key][$i] : NULL;
        }
        $transposed[] = $item;
    }
    return $transposed;
}

以下是 Codler/Andreas's solution 使用关联数组的。有点长但是 无回路 纯功能性:

<?php
function transpose($array) {
    $keys = array_keys($array);
    return array_map(function($array) use ($keys) {
        return array_combine($keys, $array);
    }, array_map(null, ...array_values($array)));
}

例子:

<?php
$foo = array(
    "fooA" => [ "a1", "a2", "a3"],
    "fooB" => [ "b1", "b2", "b3"],
    "fooC" => [ "c1", "c2", "c3"]
);

print_r( transpose( $foo ));
// Output like this:
Array (
    [0] => Array (
        [fooA] => a1
        [fooB] => b1
        [fooC] => c1
    )

    [1] => Array (
        [fooA] => a2
        [fooB] => b2
        [fooC] => c2
    )

    [2] => Array (
        [fooA] => a3
        [fooB] => b3
        [fooC] => c3
    )
);

我们可以用两个foreach。移动一个阵列和另一个阵列以创建新阵列

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

$newFoo = [];
foreach($foo as $a => $k){
   foreach($k as $i => $j){
       $newFoo[$i][]= $j;
   }
}

检查输出

echo "<pre>";
print_r($newFoo);
echo "</pre>";

在我开始之前,我想说 再次感谢@quazardus发布了他转换任意二维关联(或非关联)数组的通用解决方案!

由于我习惯于尽可能简洁地编写代码,所以我进一步“最小化”了他的代码。这将 很有可能 符合每个人的口味。但万一有人对此感兴趣,以下是我对他的解决方案的看法:

function arrayMap($cb, array $arrays) // $cb: optional callback function
{   $keys = [];
    array_walk($arrays, function ($array) use (&$keys) 
                        { $keys = array_merge($keys, array_keys($array)); });
    $keys = array_unique($keys); $res = [];
    foreach ($keys as $key) {
      $items = array_map(function ($arr) use ($key)
                         {return isset($arr[$key]) ? $arr[$key] : null; },$arrays);
      $res[$key] = call_user_func(
        is_callable($cb) ? $cb 
                         : function($k, $itms){return $itms;},
        $key, $items);
    }
    return $res;
}

array_map() ,当你打电话的时候

arrayMap(null,$b);

function transposeCsvData($data)
{
    $ct=0;
    foreach($data as $key => $val)
    {
        //echo count($val);
        if($ct< count($val))
            $ct=count($val);
        }
    //echo $ct;
    $blank=array_fill(0,$ct,array_fill(0,count($data),null));
    //print_r($blank);

    $retData = array();
    foreach ($data as $row => $columns)
    {
        foreach ($columns as $row2 => $column2) 
        {
            $retData[$row2][$row] = $column2;
            }
        }
    $final=array();
    foreach($retData as $k=>$aval)
    { 
        $final[]=array_replace($blank[$k], $aval);
       }
    return $final;
    }

测试和输出参考: https://tutes.in/how-to-transpose-an-array-in-php-with-irregular-subarray-size/

这是实现这一目标的最佳途径,

function flipDiagonally($foo){
    $temp = [];
    array_walk($foo, function($item,$key) use(&$temp){
        foreach($item as $k => $v){
            $temp[$k][$key] = $v;     
        }
    });
    return $temp;
}
$bar = flipDiagonally($foo); // Mystery function

Demo

<?php

$tableau_init = [
    [
        "prenom" => "med",
        "age" => 1
    ],
    [
        "prenom" => "hassan",
        "age" => 2
    ],
    [
        "prenom" => "ali",
        "age" => 3
    ]
];

function transpose($tableau){
    $out = array();

    foreach ($tableau as $key => $value){
        foreach ($value as $subKey => $subValue){
            $out[$subKey][$key] = $subValue;
        }
    }

    echo json_encode($out);
}

transpose($tableau_init);