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Example of specifying multi-field sorting for PHP multidimensional arrays

Jun 01, 2018 am 10:08 AM

php Field sort

This article mainly introduces examples of specifying multi-field sorting for PHP multi-dimensional arrays. It has a certain reference value. Now I share it with you. Friends in need can refer to it.

Introducing the array_multisort method

array_multisort — Sort multiple arrays or multidimensional arrays. The instructions in the PHP manual are as follows:

Copy code The code is as follows:

bool array_multisort ( array &amp;$arr [, mixed $arg = SORT_ASC [, mixed $arg = SORT_REGULAR [, mixed $... ]]] )

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Parameters

arr
An array to be sorted.

#arg
Each of the following parameters can be another array or a sorting flag option parameter for the previous array: SORT_ASC, SORT_DESC, SORT_REGULAR, SORT_NUMERIC, SORT_STRING.
…
Additional arg's.

First implement the sorting of one field of the specified multi-dimensional array

Here it is required to sort the array according to one of the fields. The array assumptions are as follows:

  $array = array(
      0=&gt;array(&#39;id&#39;=&gt;8,&#39;name&#39;=&gt;&#39;Tom&#39;),
      1=&gt;array(&#39;id&#39;=&gt;9,&#39;name&#39;=&gt;&#39;Peter&#39;),
      2=&gt;array(&#39;id&#39;=&gt;5,&#39;name&#39;=&gt;&#39;Jack&#39;)
  );

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We need to sort according to the id value of the two-dimensional array. The converted array format is as follows:

  $array = array(
      0=&gt;array(&#39;id&#39;=&gt;5,&#39;name&#39;=&gt;&#39;Jack&#39;)
      1=&gt;array(&#39;id&#39;=&gt;8,&#39;name&#39;=&gt;&#39;Tom&#39;),
      2=&gt;array(&#39;id&#39;=&gt;9,&#39;name&#39;=&gt;&#39;Peter&#39;)
  );

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To complete the above conversion, you need to use the array_multisort function introduced above, as follows:

  function sortArrByOneField(&amp;$array, $field, $desc = false){
    $fieldArr = array();
    foreach ($array as $k =&gt; $v) {
     $fieldArr[$k] = $v[$field];
    }
    $sort = $desc == false ? SORT_ASC : SORT_DESC;
    array_multisort($fieldArr, $sort, $array);
  }

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By The $field of each array in the sorted array is stored in a one-bit array fieldArr and participates in sorting in the incoming array_multisort. The value of the field array is as follows:

array(0=&gt;8,1=&gt;9,2=&gt;5)

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After passing in array_multisort, it is equivalent to sorting the $field one-dimensional array, and then rebuilding it based on the sorted key The incoming array to be sorted.

Implementing sorting of multi-dimensional arrays by specifying multiple fields

The above example explains how to implement sorting of multi-dimensional arrays by specifying one field, but if you want How to think about specifying multiple fields to sort an array?
How many fields are there? 2, 3 or more, so this uncertain factor needs to be eliminated.

Let’s first look at the 2 solutions for specifying 2 fields for sorting:

  $arr = array(
    &#39;0&#39; =&gt; array(
      &#39;id&#39; =&gt; 3,
      &#39;age&#39; =&gt; 27 
    ),
    &#39;1&#39; =&gt; array(
      &#39;id&#39; =&gt; 5,
      &#39;age&#39; =&gt; 50
    )，
    &#39;2&#39; =&gt; array(
      &#39;id&#39; =&gt; 4,
      &#39;age&#39; =&gt; 44
    ),
    &#39;3&#39; =&gt; array(
      &#39;id&#39; =&gt; 3,
      &#39;age&#39; =&gt; 78
    ) 
  );
  foreach ( $arr as $key =&gt; $row ){
    $id[$key] = $row [&#39;id&#39;];
    $age[$key] = $row [&#39;age&#39;];
  }
  array_multisort($id, SORT_ASC, $age, SORT_DESC, $arr);
  print_r($arr);
  //result:Array([0]=&gt;Array([&#39;id&#39;]=&gt;3 [&#39;age&#39;]=&gt;78) [1]=&gt;Array([&#39;id&#39;]=&gt;3 [&#39;age&#39;]=&gt;27) [2]=&gt;Array([&#39;id&#39;]=&gt;4 [&#39;age&#39;]=&gt;44) [3]=&gt;Array([&#39;id&#39;]=&gt;5 [&#39;age&#39;]=&gt;50))

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Refactor the above code, just use php The func_get_args function in can dynamically obtain the incoming value, which can solve the problem of uncertain number of multiple fields. The implementation is as follows:

  $array1 = array(
        0=&gt;array(&#39;id&#39;=&gt;8,&#39;name&#39;=&gt;&#39;Apple&#39;,&#39;age&#39;=&gt; 18),
        1=&gt;array(&#39;id&#39;=&gt;8,&#39;name&#39;=&gt;&#39;Bed&#39;,&#39;age&#39;=&gt;17),
        2=&gt;array(&#39;id&#39;=&gt;5,&#39;name&#39;=&gt;&#39;Cos&#39;,&#39;age&#39;=&gt;16),
        3=&gt;array(&#39;id&#39;=&gt;5,&#39;name&#39;=&gt;&#39;Cos&#39;,&#39;age&#39;=&gt;14)
  );
  function sortArrByManyField(){
    $args = func_get_args();
    if(empty($args)){
      return null;
    }
    $arr = array_shift($args);
    if(!is_array($arr)){
      throw new Exception(&quot;第一个参数不为数组&quot;);
    }
    foreach($args as $key =&gt; $field){
      if(is_string($field)){
        $temp = array();
        foreach($arr as $index=&gt; $val){
          $temp[$index] = $val[$field];
        }
        $args[$key] = $temp;
      }
    }
    $args[] = &amp;$arr;//引用值
    call_user_func_array(&#39;array_multisort&#39;,$args);
    return array_pop($args);
  }
  $arr = sortArrByManyField($array1,&#39;id&#39;,SORT_ASC,&#39;name&#39;,SORT_ASC,&#39;age&#39;,SORT_DESC);
  print_r($arr);

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The running result is as follows:

    array(4) {
      [0]=&gt;array(3) {
            [&quot;id&quot;]=&gt;int(5)
            [&quot;name&quot;]=&gt;string(3) &quot;Cos&quot;
            [&quot;age&quot;]=&gt;int(16)
          }
      [1]=&gt;array(3) {
            [&quot;id&quot;]=&gt;int(5)
            [&quot;name&quot;]=&gt;string(3) &quot;Cos&quot;
            [&quot;age&quot;]=&gt;int(14)
          }
      [2]=&gt;array(3) {
            [&quot;id&quot;]=&gt;int(8)
            [&quot;name&quot;]=&gt;string(5) &quot;Apple&quot;
            [&quot;age&quot;]=&gt;int(18)
          }
      [3]=&gt;array(3) {
            [&quot;id&quot;]=&gt;int(8)
            [&quot;name&quot;]=&gt;string(3) &quot;Bed&quot;
            [&quot;age&quot;]=&gt;int(17)
      }
    }

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