Directory operations in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code listing directory contents?

Consider this PHP code that reads and prints the names of files in a directory.

PHP

<?php
$dir = 'testdir';
if (is_dir($dir)) {
  if ($dh = opendir($dir)) {
    while (($file = readdir($dh)) !== false) {
      echo "$file\n";
    }
    closedir($dh);
  }
}
?>

A Lists only files in 'testdir' excluding '.' and '..'

B Lists all files and directories including '.' and '..' in 'testdir' each on a new line

C Throws a runtime error because opendir is not used correctly

D Outputs nothing because the directory is not opened

💡 Hint

Remember readdir returns '.' and '..' entries by default.

The code opens the directory and reads all entries including '.' and '..'. It prints each entry on a new line.

❓ Predict Output

intermediate

What does this PHP code output when filtering directory files?

This PHP code lists only files (not directories) inside 'myfolder'. What is the output?

PHP

<?php
$dir = 'myfolder';
$files = [];
if (is_dir($dir)) {
  if ($dh = opendir($dir)) {
    while (($file = readdir($dh)) !== false) {
      if ($file !== '.' && $file !== '..' && is_file($dir . DIRECTORY_SEPARATOR . $file)) {
        $files[] = $file;
      }
    }
    closedir($dh);
  }
}
echo count($files);
?>

A Throws a warning because DIRECTORY_SEPARATOR is undefined

B Prints the total number of entries including directories inside 'myfolder'

C Prints 0 because is_file always returns false here

D Prints the number of files (not directories) inside 'myfolder'

💡 Hint

is_file checks if the path is a regular file, not a directory.

The code counts only files, skipping '.' and '..' and directories, so it prints the number of files inside 'myfolder'.

❓ Predict Output

advanced

What error does this PHP code raise when trying to remove a directory?

This code tries to remove a directory named 'oldfolder'. What error or output occurs?

PHP

<?php
$dir = 'oldfolder';
rmdir($dir);
echo "Removed";
?>

A Warning: rmdir(): Directory not empty if 'oldfolder' has files

B Fatal error because rmdir requires a second argument

C No output because rmdir silently fails

D Removed printed even if directory does not exist

💡 Hint

rmdir only removes empty directories.

rmdir fails with a warning if the directory is not empty. It does not remove directories with files inside.

❓ Predict Output

advanced

What is the output of this PHP code creating a directory?

This PHP code tries to create a directory 'newdir' with permissions 0755. What is the output?

PHP

<?php
$dir = 'newdir';
if (mkdir($dir, 0755)) {
  echo "Created";
} else {
  echo "Failed";
}
?>

A Prints nothing because mkdir returns void

B Throws a syntax error because 0755 is not a valid permission

C Prints 'Created' if directory does not exist and is created successfully

D Prints 'Failed' if directory already exists

💡 Hint

mkdir returns true on success, false on failure.

mkdir creates the directory if it does not exist and returns true, so 'Created' is printed.

🧠 Conceptual

expert

How many items are in the array after this PHP directory scan?

This PHP code scans a directory and filters out '.' and '..'. How many items does the array contain?

PHP

<?php
$dir = 'sampledir';
$items = scandir($dir);
$filtered = array_filter($items, fn($item) => $item !== '.' && $item !== '..');
echo count($filtered);
?>

A Number of all files and directories inside 'sampledir' excluding '.' and '..'

B Number of files only inside 'sampledir'

C Always 0 because array_filter removes all items

D Number of items including '.' and '..'

💡 Hint

scandir returns all entries including '.' and '..'.

scandir returns all entries. The filter removes '.' and '..', so count is all files and directories except those two.