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How are PHP functions divided according to functionality?

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Release: 2024-04-18 13:45:02
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PHP functions are classified by function, including: string operations (str_replace, substr, etc.) numeric operations (round, abs, etc.) array operations (array_merge, array_filter, etc.) file operations (fopen, fwrite, etc.) date and time operations (date , mktime, etc.) system operations (exec, passthru, etc.)

根据功能,PHP 函数如何划分?

Divide PHP functions according to their functions

The functions in PHP are divided according to their functions Functions can be divided into the following categories:

String operations

  • str_replace: replace part of the string
  • substr: intercept characters String
  • strtoupper: Convert the string to uppercase
  • strtolower: Convert the string to lowercase

Number operations

  • round: Round a number
  • abs: Return the absolute value of a number
  • pow: Calculate the power
  • sqrt: Calculate the square root

Array operations

  • array_merge: Merge multiple arrays
  • array_filter: Filter elements in the array that meet specific conditions
  • array_map: Apply a callback function to each element in the array
  • array_reduce: Use the callback function to process the elements in the array one by one and return a single value

File operations

  • fopen: Open a file
  • fwrite: Write data to the file
  • fclose: Close a file
  • file_exists: Check whether the file exists

Date and time operations

  • date: Return the current date and time
  • mktime: Based on the specified year, month, Create timestamp of day, hour, minute, second
  • gmdate: Return Greenwich Mean Time
  • date_default_timezone_set: Set the default time zone

System operation

  • exec: Execute system commands
  • passthru: Pass system command output to the browser
  • getenv: Get environment variables
  • phpinfo: Display PHP configuration information

Practical case

The following is a sample script using PHP functions:

<?php

// 字符串操作
$originalString = "Hello World";
$newString = str_replace("World", "Universe", $originalString);

// 数字操作
$number = 12.3456;
$roundedNumber = round($number, 2);

// 数组操作
$array1 = [1, 2, 3];
$array2 = [4, 5, 6];
$mergedArray = array_merge($array1, $array2);

// 文件操作
$fileName = "myfile.txt";
$file = fopen($fileName, "w");
fwrite($file, "Hello from PHP!");
fclose($file);

// 日期和时间操作
$timestamp = 1651562400;
$formattedDate = date("Y-m-d H:i:s", $timestamp);

// 系统操作
exec("echo 'Hello from command line!'");

?>
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