Null safe operator in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to safely access the property without error if the object is null.

PHP

$length = $obj[1]->length;

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

A->

B->?

C::

D?->

Attempts:

3 left

💡 Hint

Common Mistakes

Using '->' causes an error if the object is null.

Using '::' is for static access, not for object properties.

Using '->?' is not valid syntax.

The null safe operator in PHP is '?->' which allows safe access to properties or methods even if the object is null.

2fill in blank

medium

Complete the code to safely call the method if the object is not null.

PHP

$result = $user[1]->getName();

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

A->

B::

C?->

D->?

Attempts:

3 left

💡 Hint

Common Mistakes

Using '->' causes fatal error if $user is null.

Using '::' is for static methods, not instance methods.

Using '->?' is invalid syntax.

Using '?->' calls the method only if $user is not null, otherwise returns null safely.

3fill in blank

hard

Fix the error in safely accessing the nested property.

PHP

$city = $person[1]->address[2]->city;

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

A?->

B->

C::

D->?

Attempts:

3 left

💡 Hint

Common Mistakes

Using '->' causes errors if any intermediate property is null.

Using '::' is incorrect for instance property access.

Using '->?' is invalid syntax.

Use '?->' for both property accesses to safely handle null values in the chain.

4fill in blank

hard

Fill both blanks to safely access the nested method call.

PHP

$result = $order[1]->getCustomer()[2]->getName();

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

A?->

B->

C::

D->?

Attempts:

3 left

💡 Hint

Common Mistakes

Using '->' causes errors if any method returns null.

Using '::' is for static methods only.

Using '->?' is invalid syntax.

Both method calls use '?->' to safely handle null values in the chain.

5fill in blank

hard

Fill all three blanks to safely access a deeply nested property.

PHP

$value = $config[1]->settings[2]->display[3]->theme;

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

A?->

B->

C::

D->?

Attempts:

3 left

💡 Hint

Common Mistakes

Using '->' causes fatal errors if any property is null.

Using '::' is invalid for instance properties.

Using '->?' is not valid syntax.

All property accesses use the null safe operator '?->' to avoid errors if any part is null.