String concatenation vs templates in Kotlin - Quick Revision & Key Differences

Recall & Review

beginner

What is string concatenation in Kotlin?

String concatenation is joining two or more strings using the + operator. For example, "Hello, " + "world!" results in "Hello, world!".

beginner

What are string templates in Kotlin?

String templates let you insert variables or expressions directly inside a string using the $ sign. For example, val name = "Anna"; "Hello, $name!" results in "Hello, Anna!".

intermediate

How do you include an expression inside a Kotlin string template?

Use ${expression} inside the string. For example, "Sum is ${2 + 3}" results in "Sum is 5".

beginner

Which is easier to read and maintain: string concatenation or string templates?

String templates are easier to read and maintain because they keep the string structure clear and avoid many + operators.

intermediate

Can string templates improve performance compared to concatenation?

Yes, string templates can be more efficient because Kotlin compiles them into StringBuilder operations internally, reducing overhead compared to many + concatenations.

Which symbol is used to insert a variable inside a Kotlin string template?

A $

B #

C @

D &

In Kotlin, the $ symbol is used to insert variables or expressions inside string templates.

What will the following Kotlin code print? val age = 25; println("Age: " + age)

A Error

B Age: age

C Age:

D Age: 25

Using + concatenates the string "Age: " with the value of age, printing "Age: 25".

How do you include an expression like 3 + 4 inside a Kotlin string template?

A "$3 + $4"

B "$3 + 4"

C "${3 + 4}"

D "3 + 4"

Expressions inside ${} are evaluated and inserted into the string.

Which is generally easier to read in Kotlin for combining strings and variables?

A String concatenation with +

B String templates

C Using println multiple times

D Using StringBuilder manually

String templates keep the string clear and simple, making code easier to read.

What does the following print? val name = "Sam"; println("Hello, $name!")

A Hello, Sam!

B Hello, $name!

C Hello, !

D Error

The $name inside the string template is replaced by the value of the variable name.

Explain the difference between string concatenation and string templates in Kotlin.

Think about how you combine words and variables in a sentence.

How do you include a calculation inside a Kotlin string template?

Use curly braces inside the string with a $ sign.