Settype for changing types in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code using settype?

Consider the following PHP code snippet:

$var = '123abc';
settype($var, 'int');
echo $var;

What will be printed?

PHP

$var = '123abc';
settype($var, 'int');
echo $var;

A 123

B 0

C 123abc

D Error

💡 Hint

When converting a string to int, PHP reads the number from the start until it hits a non-digit.

PHP converts the string '123abc' to integer by reading the initial digits '123'. The rest is ignored, so the output is 123.

❓ Predict Output

intermediate

What is the output after changing type to boolean?

What will this PHP code print?

$value = 0;
settype($value, 'bool');
echo $value ? 'true' : 'false';

PHP

$value = 0;
settype($value, 'bool');
echo $value ? 'true' : 'false';

A true

B false

C 0

D 1

💡 Hint

Remember that 0 is considered false in boolean context.

After settype to boolean, 0 becomes false, so the ternary prints 'false'.

❓ Predict Output

advanced

What is the output when converting an array to string with settype?

Analyze this PHP code:

$arr = [1, 2, 3];
settype($arr, 'string');
echo $arr;

What will it output?

PHP

$arr = [1, 2, 3];
settype($arr, 'string');
echo $arr;

A Error

B 1,2,3

C Array

D ArrayObject

💡 Hint

When converting an array to string, PHP returns a fixed word.

PHP converts an array to the string 'Array' when forced to string context.

❓ Predict Output

advanced

What error does this code raise when using settype with an invalid type?

Consider this PHP code:

$var = 5;
settype($var, 'unknown');

What happens when this runs?

PHP

$var = 5;
settype($var, 'unknown');

A No error, $var remains unchanged

B Parse error

C Fatal error: Unknown type

D Warning: settype() expects parameter 2 to be string of valid type

💡 Hint

PHP warns if the type string is not recognized.

settype() issues a warning if the type is invalid but does not stop execution.

🧠 Conceptual

expert

How many items are in the array after this settype operation?

What is the count of elements in $data after this code runs?

$data = '1,2,3';
settype($data, 'array');
$count = count($data);
echo $count;

PHP

$data = '1,2,3';
settype($data, 'array');
$count = count($data);
echo $count;

A 1

B 3

C 0

D Error

💡 Hint

Converting a string to array with settype wraps it inside an array.

settype converts the string into an array with one element: the original string. So count is 1.