The definition and use of is_dir() function in PHP

php provides the built-in function is_dir to check whether the incoming path parameter is a directory, and returns true if it is a directory. That is to say, if the parameter passed in is a file or does not exist, it will be false, so the current parameter cannot be said to be either a folder or a file. Another thing to note is that parameters support relative paths and absolute paths.

Function: is_dir()

Function: Determine whether the given file name is a directory

Description:
bool is_dir (string $filename)

Returns TRUE if the file name exists and is a directory.
If filename is a relative path, its relative path is checked according to the current working directory.

Note: The results of this function will be cached. See clearstatcache() for more information.

Example 1

<?
var_dump(is_dir(&#39;a_file.txt&#39;)) . "\n";
var_dump(is_dir(&#39;bogus_dir/abc&#39;)) . "\n";
var_dump(is_dir(&#39;..&#39;)); //one dir up
?>

The above example will output:

bool(false)
bool(false)
bool(true)

Example 2

<?php
$file = "images";
if(is_dir($file))
{
echo ("$file is a directory");
}
else
{
echo ("$file is not a directory");
}
?>

Output:
If the directory images exists, then output:
images is a directory

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