Null coalescing in conditions in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign $value to $input if it exists, otherwise assign 'default'.

PHP

$value = $input [1] 'default';

Drag options to blanks, or click blank then click option'

A&&

B?:

C||

D??

Attempts:

3 left

💡 Hint

Common Mistakes

Using '||' which checks for truthiness but can cause unexpected results.

Using '?:' which is the ternary shorthand but behaves differently.

The null coalescing operator ?? returns the left operand if it exists and is not null; otherwise, it returns the right operand.

2fill in blank

medium

Complete the condition to check if $data['name'] exists, otherwise use 'Guest'.

PHP

echo $data['name'] [1] 'Guest';

Drag options to blanks, or click blank then click option'

A?:

B??

C||

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using '?:' which requires the left side to be truthy, not just set.

Using '||' which can cause type coercion issues.

The ?? operator returns the left value if it exists and is not null; otherwise, it returns the right value.

3fill in blank

hard

Fix the error in the condition to assign $result to $input if set, else 'none'.

PHP

$result = [1] ?? 'none';

Drag options to blanks, or click blank then click option'

Aisset($input)

B$input ??

C$input

Dempty($input)

Attempts:

3 left

💡 Hint

Common Mistakes

Using B, which places ?? twice causing a syntax error.

Using functions like isset($input), which check existence but do not return the value.

Use the variable $input directly on the left side of the null coalescing operator ??.

4fill in blank

hard

Complete the code to assign $output to $array['key'] if set, else 'missing'.

PHP

$output = $array['key'][1] 'missing';

Drag options to blanks, or click blank then click option'

A[

B]

C??

D?:

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of brackets for array access.

Using the ternary operator instead of null coalescing.

Use square brackets to access the array key and the null coalescing operator to provide a default value.

5fill in blank

hard

Complete the code to create a condition that echoes $user['name'] if set, else 'Anonymous', and assigns it to $displayName.

PHP

$displayName = $user['name'] 'Anonymous';
echo [1];

Drag options to blanks, or click blank then click option'

A[

B??

C$displayName

D]

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to close the bracket for array access.

Echoing the array access expression instead of the variable.

Access the array key with brackets, use the null coalescing operator for default, and echo the assigned variable.