String Interpolation

Part of the Logic & Flow section of Coddy's Ruby journey — lesson 2 of 56.

Ruby lets you embed variables and expressions directly inside a double-quoted string with #{...}. This is called string interpolation.

name = "Sam"
age  = 30
puts "#{name} is #{age} years old."  # Sam is 30 years old.

The expression inside #{...} can be anything Ruby evaluates:

price = 19.5
puts "Total: $#{price * 1.2}"  # Total: $23.4

Interpolation only works in double-quoted strings. Single quotes treat #{...} as plain text.

x = 5
puts "x is #{x}"   # x is 5
puts 'x is #{x}'   # x is #{x}

Challenge

Beginner

Read a name and an age (two lines of input). Print one line in the format:

Hello, <name>! In 5 years you will be <age+5>.

For input Alice then 30, the output is:

Hello, Alice! In 5 years you will be 35.

Cheat sheet

String interpolation embeds variables/expressions in double-quoted strings using #{...}:

name = "Sam"
age  = 30
puts "#{name} is #{age} years old."  # Sam is 30 years old.
puts "Total: $#{19.5 * 1.2}"        # Total: $23.4

Single quotes treat #{...} as plain text — interpolation only works with double quotes.

Try it yourself

name = gets.chomp
age  = gets.to_i

# TODO: use string interpolation to print the message

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

1Strings In Depth

4Blocks, Procs & Lambdas

7Hashes Part 2

10Project - Student Records

2Ranges

5Enumerable Powerhouse

8Advanced Decision Making

11Final Challenges

32D Arrays

6Project - Library Manager

9Error Handling