String interpolation in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is string interpolation in Swift?

String interpolation is a way to insert values or expressions directly into a string by placing them inside \( ) within the string.

beginner

How do you insert a variable named name into a string using string interpolation?

Use \(name) inside the string. For example: "Hello, \(name)!" will insert the value of name.

intermediate

Can you use expressions inside string interpolation? Give an example.

Yes! You can put any expression inside \( ). For example: "2 + 3 = \(2 + 3)" will show 2 + 3 = 5.

intermediate

What happens if you try to use string interpolation outside of a string literal?

String interpolation only works inside string literals. Using \( ) outside strings will cause a syntax error.

beginner

Why is string interpolation useful compared to string concatenation?

String interpolation is easier to read and write. It avoids many + signs and automatically converts values to strings.

How do you insert the value of a variable age into a string using Swift string interpolation?

A "I am + age + years old"

B "I am \(age) years old"

C "I am ${age} years old"

D "I am age years old"

In Swift, string interpolation uses \(variable) inside a string literal.

Which of these is a valid string interpolation expression in Swift?

A "Sum is \(5 + 10)"

B "Sum is ${5 + 10}"

C "Sum is \{5 + 10}"

D "Sum is (5 + 10)"

Swift uses \(expression) inside strings for interpolation.

What will this Swift code print? <br> let name = "Anna"<br>print("Hello, \(name)!")

A Hello, \(name)!

B Error

C Hello, name!

D Hello, Anna!

The \(name) is replaced by the value of the variable name.

Can you use string interpolation to call a function inside a string in Swift?

A Only if the function returns a string

B No, functions cannot be used inside strings

C Yes, by placing the function call inside \( )

D Only if the function is declared inside the string

Any expression, including function calls, can be used inside \( ) in Swift strings.

What is the output of this code? <br> print("3 * 4 = \(3 * 4)")

A 3 * 4 = 12

B 3 * 4 = \(3 * 4)

C 3 * 4 = 3 * 4

D Error

The expression 3 * 4 is evaluated and inserted into the string.

Explain how string interpolation works in Swift and why it is useful.

Think about how you put values inside strings easily.

Write a Swift string that uses interpolation to show the result of 10 divided by 2.

Use \( ) inside quotes with the division expression.