How to use PHP functions to process data efficiently?

How to use PHP functions to process data efficiently

PHP provides a powerful function library that can efficiently process various data types. Understanding these functions will greatly simplify your code and improve its performance.

Array processing function

• array_map(): Apply the callback function to each element in the array and return an array containing the result.
• array_filter(): Filter the array and only retain elements that match the callback function.
• array_reduce(): Pass the array elements to the callback function one by one and return a cumulative result.
• array_unique(): Remove duplicate elements from the array.
• sort()/rsort(): Sort the array (forward or reverse order).

String processing function

• strlen(): Returns the length of the string.
• strtoupper()/strtolower(): Convert string to uppercase/lowercase.
• explode(): Split the string using the delimiter as the delimiter.
• implode(): Connect arrays using delimiters as delimiters.
• ereg_replace(): Replace the content in the string with a regular expression pattern.

Mathematical processing function

• abs(): Returns the absolute value of the number.
• max()/min(): Returns the maximum/minimum value in an array or multiple numbers.
• round(): Rounds a number to the specified precision.
• pow(): Returns the power of the number.
• log(): Returns the natural logarithm of the number.

Date and time processing functions

• date(): Return the current date and time according to the specified format.
• strtotime(): Convert a date/time string to a timestamp.
• mktime(): Create a timestamp (from the given year, month, day, hour, minute, and second).
• time(): Returns the current timestamp.
• gmstrftime(): Format time in GMT time zone.

Practical case

Processing large arrays containing student scores:

<?php

// 初始数组
$grades = [
    ['name' => 'John', 'grade' => 90],
    ['name' => 'Mary', 'grade' => 85],
    ['name' => 'Bob', 'grade' => 75],
    ['name' => 'Alice', 'grade' => 95],
];

// 使用 array_map() 计算平均成绩
$average_grades = array_map(function($student) {
    return $student['grade'] / 100;
}, $grades);

// 使用 array_filter() 获取平均成绩大于 0.9 的学生
$top_students = array_filter($grades, function($student) {
    return $student['grade'] / 100 > 0.9;
});

// 使用 array_reduce() 计算总平均成绩
$total_average = array_reduce($average_grades, function($carry, $item) {
    return $carry + $item;
}, 0) / count($average_grades);

// 打印结果
echo "平均成绩：", $total_average, "\n";
echo "平均成绩大于 0.9 的学生：", implode(", ", array_column($top_students, 'name')), "\n";

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