Tips for multidimensional sorting of PHP arrays: from novice to proficient

Multidimensional array sorting skills: Single-dimensional sorting: use the sort() function Multi-dimensional sorting: use the callback function usort() Nested sorting: use multiple callback functions to sort different fields in a specified order Practical cases: by last name and date of birth Sorting Customer List

Tips for Multidimensional Sorting of PHP Arrays: From Newbie to Mastery

Array sorting is a basic yet powerful task in PHP. When it comes to multi-dimensional arrays, things get more complicated, but by using the right techniques, we can sort them easily and efficiently.

New method

For single-dimensional sorting, we can use the sort() function:

$array = ['a', 'c', 'b'];
sort($array);
print_r($array); // ['a', 'b', 'c']

Intermediate method

Multidimensional sorting Need to use callback function:

$array = [
    ['name' => 'Alice', 'age' => 30],
    ['name' => 'Bob', 'age' => 25],
    ['name' => 'Charlie', 'age' => 35],
];

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

print_r($array); // [
    ['name' => 'Bob', 'age' => 25], 
    ['name' => 'Alice', 'age' => 30], 
    ['name' => 'Charlie', 'age' => 35]
]

Advanced method

Nested sorting Use multiple callback functions:

$array = [
    ['name' => 'Alice', 'age' => 30],
    ['name' => 'Bob', 'age' => 25, 'city' => 'New York'],
    ['name' => 'Charlie', 'age' => 35, 'city' => 'London'],
];

usort($array, function ($a, $b) {
    if ($a['age'] == $b['age']) {
        return strcmp($a['city'], $b['city']);
    }
    return $a['age'] <=> $b['age'];
});

print_r($array); // [
    ['name' => 'Bob', 'age' => 25, 'city' => 'New York'],
    ['name' => 'Alice', 'age' => 30],
    ['name' => 'Charlie', 'age' => 35, 'city' => 'London']
]

Practical case

Customer list sorting: Sort the customer list based on the customer's last name and date of birth.

$customers = [
    ['name' => 'John Doe', 'birthdate' => '1980-01-01'],
    ['name' => 'Jane Doe', 'birthdate' => '1985-03-08'],
    ['name' => 'Tom Smith', 'birthdate' => '1975-12-15'],
];

usort($customers, function ($a, $b) {
    if ($a['name'] == $b['name']) {
        return strtotime($a['birthdate']) <=> strtotime($b['birthdate']);
    }
    return strcmp($a['name'], $b['name']);
});

With these tips, you can easily sort your project's PHP multidimensional arrays efficiently, regardless of their complexity.

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