How to Use PHP is_file() to Check File Existence and Type

In PHP programming, the is_file() function is a useful tool for determining whether a given path exists and is a regular file. This article introduces its syntax, parameters, return values, and provides several code examples.

Syntax: bool is_file ( string $filename ) The function accepts a single argument $filename representing the path to check and returns true if the path points to an existing regular file, otherwise false.

Example 1 – checking a file’s existence:

<?php
$file = "/path/to/file.txt";

if (is_file($file)) {
    echo "文件存在！";
} else {
    echo "文件不存在！";
}
?>

This script defines $file, calls is_file(), and outputs a message indicating whether the file exists.

Beyond existence, is_file() also distinguishes regular files from directories or special files; it returns false for those.

Example 2 – verifying a path is a regular file:

<?php
$path = "/path/to/directory";

if (is_file($path)) {
    echo "这是一个普通文件！";
} else {
    echo "这不是一个普通文件！";
}
?>

Here $path is checked; the script prints a message based on whether the path is a regular file.

Note: to test for directories, use is_dir() instead of is_file().

In summary, is_file() is a practical PHP function for file‑system checks, and understanding its usage helps developers write more robust backend code.

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