File existence and info checks in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code checking file existence?

Consider the following PHP code snippet that checks if a file exists and prints a message accordingly. What will be the output if the file 'example.txt' does not exist in the current directory?

PHP

<?php
if (file_exists('example.txt')) {
    echo 'File found';
} else {
    echo 'File not found';
}
?>

A File not found

B Warning: file_exists(): Unable to access example.txt

C Fatal error: Uncaught Error

D File found

💡 Hint

file_exists() returns false if the file is not present.

The function file_exists() returns false if the file does not exist, so the else branch runs and prints 'File not found'.

❓ Predict Output

intermediate

What does this PHP code output about file size?

Given the PHP code below, what will be the output if the file 'data.log' exists and its size is 2048 bytes?

PHP

<?php
$size = filesize('data.log');
echo "Size: $size bytes";
?>

A Size: 2048 bytes

B Warning: filesize(): stat failed for data.log

C Size: 0 bytes

D Size: bytes

💡 Hint

filesize() returns the size in bytes of the file if it exists.

Since 'data.log' exists and is 2048 bytes, filesize() returns 2048 and the echo prints 'Size: 2048 bytes'.

🔧 Debug

advanced

Why does this PHP code checking if a path is a directory fail?

The following PHP code is intended to check if 'myfolder' is a directory and print a message. However, it always prints 'Not a directory' even when 'myfolder' exists and is a directory. What is the cause?

PHP

<?php
if (is_dir('myfolder/')) {
    echo 'It is a directory';
} else {
    echo 'Not a directory';
}
?>

A The directory 'myfolder' does not have read permissions

B The trailing slash in 'myfolder/' causes is_dir() to fail

C The code is correct; the problem is elsewhere

D The function is_dir() requires an absolute path, not relative

💡 Hint

Check file system permissions for the directory.

The trailing slash in 'myfolder/' does not cause is_dir() to fail. is_dir() works with relative paths and trailing slashes. If the directory exists and permissions are correct, the code is correct. Therefore, the problem is elsewhere.

📝 Syntax

advanced

Which option causes a syntax error in PHP file info check?

Which of the following PHP code snippets will cause a syntax error when checking if a file is readable?

A <?php if (is_readable('file.txt')) { echo 'Readable'; } ?>

B <?php if is_readable('file.txt') { echo 'Readable'; } ?>

C <?php if (is_readable('file.txt')) echo 'Readable'; ?>

D <?php if (is_readable('file.txt')) { echo 'Readable'; } else { echo 'Not readable'; } ?>

💡 Hint

Check the syntax of the if statement.

Option B is missing parentheses around the condition in the if statement, causing a syntax error.

🚀 Application

expert

How many items are in the array returned by this PHP file info code?

This PHP code uses stat() to get file info. How many elements does the array returned by stat('test.txt') contain?

PHP

<?php
$info = stat('test.txt');
echo count($info);
?>

A 13

B 15

C 12

D 26

💡 Hint

stat() returns an array with both numeric and associative keys.

stat() returns an array with 26 elements: 13 numeric keys and 13 associative keys with the same values.