交换多维数组中的第一个和最后一个数组

Question

我有一个多维数组，格式如下

$pet = array(
     array(
            'name' => 'Chew Barka',
            'breed' => 'Bichon',
            'age'  => '2 years',
            'weight' => 8,
         'bio'   => 'The park, The pool or the Playground - I love to go anywhere! I am really great at... SQUIRREL!',
            'filename' => 'pet1.png'
    ),
    array(
            'name' => 'Spark Pug',
            'breed' => 'Pug',
            'age'  => '1.5 years',
            'weight' => 11,
            'bio'   => 'You want to go to the dog park in style? Then I am your pug!',
            'filename' => 'pet2.png'
    ),
    array(
        'name' => 'Pico de Gato',
            'breed' => 'Bengal',
            'age'  => '5 years',
            'weight' => 9,
            'bio'   => 'Oh hai, if you do not have a can of salmon I am not interested.',
            'filename' => 'pet3.png'
    ),
    array(
        'name' => 'Name',
            'breed' => 'Breed',
            'age'  => 'Age',
            'weight' => 'Weight',
            'bio'   => 'Biography',
            'filename' => 'Filename'
    )
);

我需要将最后一个数组与第一个数组交换。我试过这样做

function arraySwap(&$array, $swap_a, $swap_b){
    list($array[$swap_a], $array[$swap_b]) = array($array[$swap_b], $array[$swap_a]);
}

这会先与最后交换数组。但是我需要的是将数组推到下面。因此，一旦我将最后一个数组与第一个数组交换，第一个数组需要到达位置 1，位置 1 的位置到达 2，依此类推。

谁能指出我正确的方向？

Answer 1

您可以只从数组中分割第一个和最后一个项目，然后 re-assemble 使用 array_merge。

示例：

function swapFirstAndLast($array) {
    return array_merge(
        array_slice($array, -1 , 1), // Last item
        array_slice($array, 1 , count($array) - 2), // Second - Second last items
        array_slice($array, 0 , 1) // First item
    );
}

var_dump(array_column(swapFirstAndLast($pet), 'name'));

//array(4) {
//    [0] =>
//  string(4) "Name"
//    [1] =>
//  string(9) "Spark Pug"
//    [2] =>
//  string(12) "Pico de Gato"
//    [3] =>
//  string(10) "Chew Barka"
//}

Answer 2

我想你只是想移动顶部的标题数组，你可以像下面那样做一些圆形数组移动

$arr = array(
     array(
            'name' => 'Chew Barka',
            'breed' => 'Bichon',
            'age'  => '2 years',
            'weight' => 8,
         'bio'   => 'The park, The pool or the Playground - I love to go anywhere! I am really great at... SQUIRREL!',
            'filename' => 'pet1.png'
    ),
    array(
            'name' => 'Spark Pug',
            'breed' => 'Pug',
            'age'  => '1.5 years',
            'weight' => 11,
            'bio'   => 'You want to go to the dog park in style? Then I am your pug!',
            'filename' => 'pet2.png'
    ),
    array(
        'name' => 'Pico de Gato',
            'breed' => 'Bengal',
            'age'  => '5 years',
            'weight' => 9,
            'bio'   => 'Oh hai, if you do not have a can of salmon I am not interested.',
            'filename' => 'pet3.png'
    ),
    array(
        'name' => 'Name',
            'breed' => 'Breed',
            'age'  => 'Age',
            'weight' => 'Weight',
            'bio'   => 'Biography',
            'filename' => 'Filename'
    )
);

echo "<pre>";
$key=count($arr)-1;
$output1 = array_slice($arr, $key); 
$output2 = array_slice($arr, 0,$key); 
$new=array_merge($output1,$output2);
print_r($new);

输出

Array
(
    [0] => Array
        (
            [name] => Name
            [breed] => Breed
            [age] => Age
            [weight] => Weight
            [bio] => Biography
            [filename] => Filename
        )

    [1] => Array
        (
            [name] => Chew Barka
            [breed] => Bichon
            [age] => 2 years
            [weight] => 8
            [bio] => The park, The pool or the Playground - I love to go anywhere! I am really great at... SQUIRREL!
            [filename] => pet1.png
        )

    [2] => Array
        (
            [name] => Spark Pug
            [breed] => Pug
            [age] => 1.5 years
            [weight] => 11
            [bio] => You want to go to the dog park in style? Then I am your pug!
            [filename] => pet2.png
        )

    [3] => Array
        (
            [name] => Pico de Gato
            [breed] => Bengal
            [age] => 5 years
            [weight] => 9
            [bio] => Oh hai, if you do not have a can of salmon I am not interested.
            [filename] => pet3.png
        )

)

Answer 3

有很多方法可以给这只猫剥皮。这里有两个函数，第一个总是交换第一个和最后一个元素，第二个交换任意元素。我已经展示了如何使用该函数轻松交换首尾。您可以在 arraySwapFirstLast 函数中使用 arraySwap 函数中的逻辑而不是 array_shift, array_unshift, and array_pop，这可能会更有效，但这演示了一些重要的数组操作函数。 arraySwap 中的简单逻辑是您在教科书排序算法中使用的逻辑，非常高效。

<?php
$pet = array(
    array(
        'name' => 'Chew Barka',
        'breed' => 'Bichon',
        'age'  => '2 years',
        'weight' => 8,
        'bio'   => 'The park, The pool or the Playground - I love to go anywhere! I am really great at... SQUIRREL!',
        'filename' => 'pet1.png'
    ),
    array(
        'name' => 'Spark Pug',
        'breed' => 'Pug',
        'age'  => '1.5 years',
        'weight' => 11,
        'bio'   => 'You want to go to the dog park in style? Then I am your pug!',
        'filename' => 'pet2.png'
    ),
    array(
        'name' => 'Pico de Gato',
        'breed' => 'Bengal',
        'age'  => '5 years',
        'weight' => 9,
        'bio'   => 'Oh hai, if you do not have a can of salmon I am not interested.',
        'filename' => 'pet3.png'
    ),
    array(
        'name' => 'Name',
        'breed' => 'Breed',
        'age'  => 'Age',
        'weight' => 'Weight',
        'bio'   => 'Biography',
        'filename' => 'Filename'
    )
);

$pet1 = $pet;
$pet2 = $pet;

/**
 * Swap the first and last elements of an array
 * Uses shift/unshift and standard array append
 * @param $array
 */
function arraySwapFirstLast(&$array)
{
    $first = array_shift($array);
    $last  = array_pop($array);
    array_unshift($array, $last);
    $array[] = $first;
}

/**
 * Swap two arbitrary array elements
 * @param $array
 * @param $index1
 * @param $index2
 */
function arraySwap(&$array, $index1, $index2)
{
    $swapEl = $array[$index1];

    $array[$index1] = $array[$index2];
    $array[$index2] = $swapEl;
}

arraySwapFirstLast($pet);
echo 'arraySwapFirstLast:'.PHP_EOL;
print_r($pet).PHP_EOL;

arraySwap($pet1, 1, 2);
echo 'arraySwap second and third elements:'.PHP_EOL;
print_r($pet1).PHP_EOL;

arraySwap($pet2, 0, sizeof($pet2)-1);
echo 'arraySwap first and last elements:'.PHP_EOL;
print_r($pet2).PHP_EOL;

Answer 4

你可以使用：

$arr1 = $pet[0];
$arr2 = $pet[count($pet)-1];
$pet[0] = $arr2;
$pet[count($pet)-1] = $arr1;
print_r($pet);

交换多维数组中的第一个和最后一个数组

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