File.readlines for line-by-line in Ruby - Mini Project: Build & Apply

Reading a File Line-by-Line with File.readlines in Ruby

📖 Scenario: You have a text file named colors.txt that contains a list of colors, one color per line. You want to read this file line-by-line to process each color.

🎯 Goal: Build a Ruby program that reads the colors.txt file line-by-line using File.readlines and prints each color in uppercase.

📋 What You'll Learn

Create a variable called colors that reads all lines from colors.txt using File.readlines

Create a variable called count and set it to 0

Use a for loop with variable color to iterate over colors

Inside the loop, print each color in uppercase

After the loop, print the total number of colors read

💡 Why This Matters

🌍 Real World

Reading files line-by-line is common when processing logs, configuration files, or data lists.

💼 Career

Many programming jobs require reading and processing text files efficiently, especially in scripting and automation.

1

Read all lines from the file

Create a variable called colors that reads all lines from the file colors.txt using File.readlines.

Ruby

# Your code here

Need a hint?

Use File.readlines('colors.txt') to read all lines into an array.

2

Create a counter variable

Create a variable called count and set it to 0 to count the number of colors.

Ruby

colors = File.readlines('colors.txt')
# Your code here

Need a hint?

Initialize count to zero before counting.

3

Loop through each color and print uppercase

Use a for loop with variable color to iterate over colors. Inside the loop, print each color in uppercase and increase count by 1.

Ruby

colors = File.readlines('colors.txt')
count = 0
# Your code here

Need a hint?

Use for color in colors to loop. Use color.chomp.upcase to print uppercase without extra newlines.

4

Print the total number of colors

After the loop, print the total number of colors read using puts and the count variable.

Ruby

colors = File.readlines('colors.txt')
count = 0
for color in colors
  puts color.chomp.upcase
  count += 1
end
# Your code here

Need a hint?

Use puts "Total colors: #{count}" to print the count after the loop.