How to write files without overwriting in php

Method: 1. Use "file_put_contents(file name,'data',FILE_APPEND)"; 2. Use "fwrite(fopen(file name,'a'),'data')", fopen() Files can be opened in append mode, and fwrite() can write data in the opened file.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

How to implement files in php Writing without overwriting

In PHP, if you want to write a file without overwriting, you can do so by appending data to the end of the file.

PHP supports two methods of appending data to the end of the file:

• Use the file_put_contents() function

• Use fopen( ) and fwrite() function

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

Let’s see how to write data to a file (without overwriting):

Method 1: Use the file_put_contents() function to append data

The file_put_contents() function can The string is written to the file. The syntax format is as follows:

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

The parameter description is as follows:

• $filename: the file name 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 (you can use | operator combination):
  • 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.

Set the third parameter of the file_put_contents() function to "FILE_APPEND" to append data instead of overwriting.

Example:

<?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);    //写入内容
readfile($file);   //读取并输出文件全部内容
?>

Method 2: Use fopen() and fwrite() functions to append data

<?php
header("Content-Type: text/html;charset=utf-8");    //设置字符编码
$file = "test.txt";
$handle = fopen($file, &#39;a&#39;);                 //以追加写入的模式打开文件
fwrite($handle, &#39;https://www.php.cn/&#39;);    //写入内容
fclose($handle);//关闭文件
readfile($file);   //读取并输出文件全部内容
?>

Key code analysis:

• fopen($filename, $mode)The function can follow the specified file mode$ modeOpen a file. When $mode is a or a , set the file pointer to the end of the file when opening the file; in this way, when writing, the data will be appended to Behind the existing data.

• fwrite()The function can write a string to an open file, so fwrite($handle, 'https://www .php.cn/') statement is to write the string "https://www.php.cn/" into the already opened "test.txt".

• After writing is completed, use the fclose() function to close the file. If you want to get the new content in the "test.txt" file, use the readfile($file) function to get it directly.

Recommended learning: "PHP Video Tutorial"

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