PHP按strnatcmp和另一个特定关键字排序

Question

• I need to sort an multi dimensional array which looks like this down below (usort already applied).
• I need to move '10000_M3' to the first key if an identifier '_M' was found (as natural sorting), but the order from 'first' sort should not be touched.
• Extra: (Optional) If i have a description like '10000_0', it should be still in index 0
• If the usort can be done in 1 step would be great

• I take any solution (usort, foreach, ..)!!!

  usort($anArray, function ($a, $b) {
      return strnatcmp($a['description'], $b['description']);
  });
  
  $anArray = [
      // ? => [
      //     'description' => '10000_0'
      // ]
      0 => [
          'description' => '10000_D2'
      ],
      1 => [
          'description' => '10000_D3'
      ],
      2 => [
          'description' => '10000_M3'
      ],
      3 => [
          'description' => '10000_M4'
      ]
  ]
  

Result (Natural -> at first position = '_0' -> $ident = '_M' after '_0' if its exists):

    $result = [
        0 => [
            'description' => '10000_0'
        ]
        1 => [
            'description' => '10000_M3'
        ],
        2 => [
            'description' => '10000_M4'
        ]
        3 => [
            'description' => '10000_D2'
        ],
        4 => [
            'description' => '10000_D3'
        ],
    ]

Answer 1

You can modify your sort function to check for the special cases individually then fall back on a regular sorting method.

<?php
$inputArray = [
    0 => [
        'description' => '10000_D2'
    ],
    1 => [
        'description' => '10000_D3'
    ],
    2 => [
        'description' => '10000_M3'
    ],
    3 => [
        'description' => '10000_M4'
    ],
    4 => [
         'description' => '10000_0'
    ]
];

usort($inputArray, function ($a, $b) {
    // _0 first then _M* then alphabetic

    //assume only 1 value will be _0?
    if (preg_match('/_0$/', $a['description']) === 1){
        //"a" ends in _0
        return -1;
    }
    if (preg_match('/_0$/', $b['description']) === 1){
        //"b" ends in _0
        return 1;
    }

    if (
        preg_match('/_M\d*$/', $a['description']) === 1
        && preg_match('/_M\d*$/', $b['description']) === 1
    ){
        //both have "M" so sort them normally
        return strnatcmp($a['description'], $b['description']);
    }

    if (preg_match('/_M\d*$/', $a['description']) === 1){
        //only "a" has _M
        return -1;
    }

    if (preg_match('/_M\d*$/', $b['description']) === 1){
        //only "b" has _M
        return 1;
    }

    //neither side has _M or _0 so normal sorting
    return strnatcmp($a['description'], $b['description']);
});

echo print_r($inputArray, true);
?>

Output:

Array
(
    [0] => Array
        (
            [description] => 10000_0
        )

    [1] => Array
        (
            [description] => 10000_M3
        )

    [2] => Array
        (
            [description] => 10000_M4
        )

    [3] => Array
        (
            [description] => 10000_D2
        )

    [4] => Array
        (
            [description] => 10000_D3
        )

)

I'm assuming you will only have a single _0 value. If you could have multiple _0 values then you need to modify the above code to behave like the 3 _M "if" statements.