PHP：如何通过子数组的值来排序数组[重复]

Question

This question already has an answer here:

• How can I sort arrays and data in PHP? 10 answers

Is it possible to order the below by the value of the child arrays, eg: age or height?

array (
  "John" => array (
    "height"=>175,
    "weight"=>85,
    "age"="24"
  ),
  "Phil" => array (
    "height"=>185,
    "weight"=>75,
    "age"="22"
  )
 "Jim" => array (
    "height"=>195,
    "weight"=>140,
    "age"="29"
  )
)

Eg outputting the order by age would be: Phil, John, Jim.

Is this possible with PHP?

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Answer 1

Use usort: If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

function sortByAge($a, $b) {
    return $a['age'] - $b['age'];
}

usort($myArray, 'sortByAge');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['age'] - $b['age'];
});

And finally with PHP 7 you can use the "spaceship operator":

usort($myArray, function($a, $b) {
    return $a['age'] <=> $b['age'];
});

Source: Sort Multi-dimensional Array by Value