How to sort and filter data using PHP functions?

PHP provides a variety of functions to sort and filter data, including sort() (ascending order), rsort() (descending order), array_filter() (filter based on conditions), array_map() (application operation) and array_reduce() (cumulative operation). These functions allow you to easily perform data operations such as sorting by order date and filtering order total amount.

How to use functions to sort and filter data in PHP

PHP provides a variety of built-in functions that allow you to Sort and filter array data easily.

Sort function

• sort(): Sort the values ​​in the array in ascending order.
• rsort(): Sort the values ​​in the array in descending order.
• asort(): Sort the array key-value pairs in ascending order.
• arsort(): Sort the array key-value pairs in descending order.
• ksort(): Sort array key-value pairs by key.
• krsort(): Sort the array key-value pairs in descending order by key.

Example:

$numbers = [5, 2, 8, 1, 4];

sort($numbers); // 排序 $numbers 数组
print_r($numbers); // 输出： [1, 2, 4, 5, 8]

Filter function

• array_filter():Filter the array according to the given callback function and retain elements that meet the conditions.
• array_map(): Apply an operation to each element in the array based on the given callback function and return a new array.
• array_reduce(): Performs an accumulation operation on each element in the array according to the given callback function and returns a single value.

Example:

$users = [
    ['name' => 'John', 'age' => 30],
    ['name' => 'Mary', 'age' => 25],
    ['name' => 'Bob', 'age' => 40],
];

$filteredUsers = array_filter($users, function ($user) {
    return $user['age'] >= 30;
}); // 过滤年龄大于或等于 30 岁的人

print_r($filteredUsers); // 输出： [['name' => 'John', 'age' => 30], ['name' => 'Bob', 'age' => 40]]

Practical case

Suppose you have a data set containing e-commerce orders, You need to sort the orders by order date in ascending order and filter out orders with a total order amount greater than $100.

$orders = [
    [
        'order_date' => '2023-03-01',
        'total_amount' => 120
    ],
    [
        'order_date' => '2023-02-15',
        'total_amount' => 80
    ],
    [
        'order_date' => '2023-04-05',
        'total_amount' => 150
    ],
    [
        'order_date' => '2023-03-10',
        'total_amount' => 90
    ],
];

// 对订单按日期升序排序
usort($orders, function ($a, $b) {
    return strtotime($a['order_date']) - strtotime($b['order_date']);
});

// 过滤出订单总金额大于 100 美元的订单
$filteredOrders = array_filter($orders, function ($order) {
    return $order['total_amount'] > 100;
});

print_r($filteredOrders); // 输出： [[...]，...]

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