Type coercion in operations in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is type coercion in PHP?

Type coercion is when PHP automatically converts one data type to another during operations, like turning a string into a number when needed.

beginner

What happens when you add a string containing a number to an integer in PHP?<br>

$result = '5' + 3;

PHP converts the string '5' to the number 5, then adds 3, so $result becomes 8.

intermediate

How does PHP treat a string that starts with numbers but has letters after when used in arithmetic?<br>

$result = '10abc' + 5;

PHP reads the starting number 10 and ignores the letters, so it adds 10 + 5 = 15.

beginner

What is the result of adding a boolean to an integer in PHP?<br>

$result = true + 2;

PHP converts true to 1, so the result is 1 + 2 = 3.

intermediate

What happens when you add a non-numeric string to a number in PHP?<br>

$result = 'hello' + 5;

PHP converts the non-numeric string to 0, so the result is 0 + 5 = 5.

What does PHP do when adding '7' + 3?

A Keeps '7' as string and ignores 3

B Concatenates '7' and 3 to '73'

C Throws an error

D Converts '7' to number 7 and adds to 3

PHP automatically converts the string '7' to the number 7 and then adds 3, resulting in 10.

What is the result of '12abc' + 8 in PHP?

A 20

B 12abc8

C Error

D 8

PHP reads the numeric part '12' and adds 8, resulting in 20.

How does PHP treat true when used in arithmetic?

A As 1

B As 0

C As true

D Throws an error

PHP converts true to 1 in arithmetic operations.

What happens when you add 'hello' + 5 in PHP?

A Error

B hello5

C 5

D hello

Non-numeric strings convert to 0, so 0 + 5 = 5.

Which of these is NOT a type PHP coerces automatically?

A Boolean to number

B Array to number

C String to number

D Integer to float

PHP does not automatically convert arrays to numbers in arithmetic operations.

Explain how PHP handles type coercion when adding a string and a number.

Think about how PHP reads the string before adding.

Describe what happens when a boolean is used in an arithmetic operation in PHP.

Booleans act like small numbers in math.