How to determine if a file exists in php

php method to determine whether a file exists: first create a PHP sample file; then use the "file_exists(string $filename)" syntax to determine whether the file or directory exists.

#The operating environment of this article: Windows7 system, PHP7.1, Dell G3 computer.

Before operating on a file, in order to avoid errors, you should first determine whether the file exists, because opening a file that does not exist will cause the program to error and stop.

PHP provides us with a special function to do this work, this function is file_exists(). The file_exists() function can determine whether the file or directory exists. If it exists, the function returns TRUE, otherwise it returns FALSE. The syntax of the function is as follows:

file_exists(string $filename)

Among them, the parameter $filename is the path of the file or directory.

[Example] Use the file_exists() function to determine whether a file exists.

<?php
    $file = &#39;test.txt&#39;;
    if(file_exists($file)){
        echo $file.&#39; 存在！&#39;;
    }else{
        echo $file.&#39; 不存在！&#39;;
    }
?>

The running results are as follows:

test.txt 存在！

Note: Due to security considerations, the file name parameter of the file_exists() function cannot be a remote file, for example, execute file_exists('http://c.biancheng. net/index.html'), the function will return FALSE regardless of whether the file exists.

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