For Loop with Ranges

Loops let you repeat code multiple times without writing it over and over. In Ruby, the for loop combined with a range is a straightforward way to iterate through a sequence of numbers.

A range in Ruby represents a sequence of values. You create one using two dots between a start and end value. Here's how to loop through numbers 1 to 5:

for i in 1..5
  puts i
end

This outputs each number from 1 to 5, each on its own line. The variable i takes on each value in the range, one at a time, and the code inside the loop runs for each value.

Ruby has two types of ranges. The two-dot range 1..5 includes both endpoints (1, 2, 3, 4, 5). The three-dot range 1...5 excludes the last number (1, 2, 3, 4):

for num in 1...4
  puts num
end
# Outputs: 1, 2, 3

You can use any variable name you like and perform operations inside the loop. For example, printing the square of each number:

for n in 1..3
  puts n * n
end
# Outputs: 1, 4, 9