How to delete a specified string in a file in php

PHP is a popular programming language used in web development. In the process of web development, file operations are common operations. Sometimes we need to delete certain strings in the file, so how to achieve it? This article will show you how to delete a specified string from a file using PHP.

1. Open the file

First, you need to open the file that needs to be operated. We can use PHP's built-in function fopen to open the file, specify the opening mode as r , and open the file in read-write mode:

$file = 'test.txt';
$handle = fopen($file, 'r+');

In the above code, test .txt is the file name that needs to be operated, r is the opening mode.

2. Get the file content

Next, we need to get the file content, we can use the PHP built-in function fread to read:

$content = fread($handle, filesize($file));

In the above code, the filesize function is used to obtain the file size, and the fread function is used to read the contents of the file.

3. Delete the specified string

Next, we need to delete the specified string. We can use the PHP built-in function str_replace to achieve:

$oldStr = 'hello';
$newStr = '';
$content = str_replace($oldStr, $newStr, $content);

In the above code, the str_replace function is used to replace the in $content $oldStr is replaced with $newStr, thereby deleting all $oldStr strings.

4. Rewrite the file

Finally, we need to rewrite the contents after the operation into the file, which can be done using the PHP built-in function fwrite Write:

rewind($handle);
fwrite($handle, $content);
fclose($handle);

In the above code, the rewind function is used to reset the file pointer to the beginning of the file, and the fwrite function is used to write the operation content In the file, the fclose function is used to close the file.

The complete code is as follows:

$file = 'test.txt';
$handle = fopen($file, 'r+');
$content = fread($handle, filesize($file));
$oldStr = 'hello';
$newStr = '';
$content = str_replace($oldStr, $newStr, $content);
rewind($handle);
fwrite($handle, $content);
fclose($handle);

The above is how to use PHP to delete the specified string in the file. In the actual development process, we can make appropriate modifications according to needs to achieve the results we want.

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