What are the most commonly used functions in PHP?

The most commonly used functions in PHP include: data operations: var_dump(), print_r(), array() string operations: strlen(), strtoupper(), substr() file processing: fopen(), fwrite() , fread() error handling: error_reporting(), trigger_error(), set_error_handler()

The most commonly used functions in PHP

PHP provides a wide range of functions for performing a variety of tasks, from data processing to string manipulation. This article will explore some of the most widely used functions in PHP, including:

Data manipulation

• var_dump(): in human readable form Format print variable value.
• print_r(): Print structural information (fields and values) about variables.
• array(): Create or initialize an array.

String operations

• strlen(): Get the string length.
• strtoupper(): Convert the string to uppercase.
• substr(): Extract part of the string.

File handling

• fopen(): Open a file for reading and writing.
• fwrite(): Write data to the file.
• fread(): Read data from the file.

Error handling

• error_reporting(): Control which errors are displayed.
• trigger_error(): Manually trigger errors.
• set_error_handler(): Custom error handling function.

Practical Case

The following is an example of how to use some of the above functions:

<?php

// 数据操作
$array = array(1, 2, 3);
print_r($array); // 输出：Array ( [0] => 1 [1] => 2 [2] => 3 )

// 字符串操作
$str = "Hello world";
echo strlen($str); // 输出：11
echo strtoupper($str); // 输出：HELLO WORLD

// 文件处理
$file = fopen("myfile.txt", "w");
fwrite($file, "Hello world");
fclose($file);

?>

Conclusion

The PHP function library contains a wide range of tools that can be used to solve various programming tasks. Understanding these most commonly used functions is crucial in order to write PHP applications effectively.

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