What is the function to modify files in php

Modify function: 1. fwrite(), you can write a string to a file, the syntax is "fwrite(specify file, write data, number of bytes written)"; 2. file_put_contents( ), syntax "file_put_contents(file name, written data, writing mode)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

There are two functions in php to modify files: fwrite () and file_put_contents() function

1, fwrite() function

fwrite() function can write a string to a file, the syntax format of the function As follows:

fwrite(resource $handle, string $string[, int $length])

The parameter description is as follows:

• $handle: The file to be written is the resource created by fopen();

• $string: The string to be written;

• $length: Optional parameter, used to set the number of bytes to be written.

The fwrite() function can write the contents of $string to the file pointer $handle. If $length is specified, writing will stop when $length bytes have been written or $string has been written. If the function is successfully executed, the number of bytes written will be returned. If the function fails, FALSE will be returned.

Example: There is a text file named "test.txt", the content is:

##

<?php
header("Content-Type: text/html;charset=utf-8");    //设置字符编码
$file = "test.txt";
$handle = fopen($file, &#39;w&#39;);                 //打开文件
fwrite($handle, &#39;HELLO PHP!&#39;);    //写入内容
fclose($handle);//关闭文件
?>

After writing the content, we read File

readfile($file);   //读取并输出文件全部内容

Look at the output result:

Re-open the "test.txt" file and look at the content:

As you can see, we clear the file and re-add the data.

2. file_put_contents() function

file_put_contents() function has the same function as fwrite() function. It can also write a string to a file. The syntax format As follows:

file_put_contents(string $filename, mixed $data[, int $flags = 0[, resource $context]])

Parameter description is as follows:

$filename: The name of the file to which data is to be written;
• $data: The data to be written can be a string, one-dimensional array or resource type;
• $flags: Optional parameter, its value can be the following (can be used in combination with the
• | operator):
              FILE_USE_INCLUDE_PATH: Search for $filename in the include directory.
  •             FILE_APPEND: If file $filename already exists, append data instead of overwriting.
  •             LOCK_EX: Obtain an exclusive lock while writing.
$context: Optional parameter, a context resource.

Same as the fwrite() function. The file_put_contents() function will return the number of bytes of data written to the file if executed successfully. If failed, it will return a Boolean value of FALSE or a non-Boolean value equivalent to FALSE.

Example 1: Clear the file and re-add the data

<?php
header("Content-Type: text/html;charset=utf-8");    //设置字符编码
$file = "test.txt";
file_put_contents($file, &#39;欢迎来到PHP中文网！&#39;);    //写入内容
readfile($file);   //读取并输出文件全部内容
?>

The output result is:

Reopen the "test.txt" file and see Look at the content:

Example 2: Append writing data at the end of the file

<?php
header("Content-Type: text/html;charset=utf-8");    //设置字符编码
$file = "test.txt";
file_put_contents($file, &#39;欢迎来到PHP中文网！33&#39;,FILE_APPEND|LOCK_EX);    //写入内容
readfile($file);   //读取并输出文件全部内容
?>

Reopen the "test.txt" file and look at the content:

Recommended learning: "

PHP Video Tutorial"

The above is the detailed content of What is the function to modify files in php. For more information, please follow other related articles on the PHP Chinese website!