Example of converting one-dimensional array to two-dimensional array in PHP

The previous two articles "What is a php one-dimensional array, a detailed explanation of a php one-dimensional array example" and "What is a php two-dimensional array, a detailed explanation of a php two-dimensional array example 》Introducing one-dimensional arrays and two-dimensional arrays in detail. In this chapter, I will introduce the implementation of mutual conversion between one-dimensional arrays and two-dimensional arrays!

Without further ado, let’s first introduce the sample code for converting a one-dimensional array into a two-dimensional array:

<?php
header("Content-Type:text/html; charset=utf-8");
$asr[1] = array("a","b","c","d");
$asr[2] = array("a","b","c","d");
$asr[3] = array("a","b","c","d");
$newarray = array();
foreach($asr as $a)
{
    $newarray[] = $a;
}
print_r($newarray);
?>

The output result is:

Array (
[0] => Array (
[0] => a
[1] => b
[2] => c
[3] => d )
[1] => Array (
[0] => a
[1] => b
[2] => c
[3] => d )
[2] => Array (
[0] => a
[1] => b
[2] => c
[3] => d )
)

2 ways to convert a two-dimensional array into a one-dimensional array:

How to convert the following two-dimensional array into a one-dimensional array.

<?php
header("Content-Type:text/html; charset=utf-8");
$msg = array(
  array(
    &#39;id&#39;=>&#39;45&#39;,
    &#39;name&#39;=>&#39;jack&#39;
  ),
  array(
    &#39;id&#39;=>&#39;34&#39;,
    &#39;name&#39;=>&#39;mary&#39;
  ),
  array(
    &#39;id&#39;=>&#39;78&#39;,
    &#39;name&#39;=>&#39;lili&#39;
  ),
);
?>

The first method:

foreach($msg as $k => $v){
        $ids[] = $id;
        $names[] = $name;
      }

The second method:

$ids = array_column($msg, 'id');
$names = array_column($msg, 'name');

The result of the above two solutions print_r($names); is:

Array(
　　[0]=>jack
　　[1]=>mary
　　[2]=>lili
)

Note: array_column(); can have a third parameter, such as $n = array_column($msg, 'name', 'id');

print_r($n);The result is:

Array(
　　[45]=>jack
　　[34]=>mary
　　[78]=>lili
)

【Related tutorial recommendations】

1. Relevant topic recommendations: "php array (Array)"

2 . Related video course recommendations: " Sort multiple arrays at the same time. Multidimensional arrays are first converted into one-dimensional arrays by value: array_multisort()"

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