PHP function to determine whether it is a directory

php is_dir() function introduction

is_dir — Determine whether the given file name is a directory

Syntax: (Recommended learning: PHP Programming from entry to proficiency)

bool is_dir ( string $filename )

Determine whether the given file name is a directory.

Parameters:

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

Return value:

If the file name exists and is a directory, return TRUE, otherwise return FALSE.

php is_dir() example

/**
 * 判断 文件/目录 是否可写（取代系统自带的 is_writeable 函数）
 *
 * @param string $file 文件/目录
 * @return boolean
 */
function new_is_writeable($file) {
    if (is_dir($file)){
        $dir = $file;
        if ($fp = @fopen("$dir/test.txt", 'w')) {
            @fclose($fp);
            @unlink("$dir/test.txt");
            $writeable = 1;
        } else {
            $writeable = 0;
        }
    } else {
        if ($fp = @fopen($file, 'a+')) {
            @fclose($fp);
            $writeable = 1;
        } else {
            $writeable = 0;
        }
    }
 
    return $writeable;
}

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