Break

In Ruby, the break keyword is used to exit a loop or block prematurely. Unlike next which skips to the next iteration, break terminates the loop entirely and continues with the code after the loop.

# Basic break usage in a loop
5.times do |i|
  break if i == 3

  puts i
end
# Output:
# 0
# 1
# 2

The break statement can be used with any of Ruby’s iteration methods or loops.

array = [1, 2, 3, 4, 5]

# Break in each iteration
array.each do |num|
  break if num > 3

  puts "Number: #{num}"
end
# Output:
# Number: 1
# Number: 2
# Number: 3

# Break in an infinite loop
count = 0
loop do
  count += 1
  break if count >= 3

  puts "Count: #{count}"
end
# Output:
# Count: 1
# Count: 2

Break with a Value

When used inside a block, break can return a value that becomes the result of the method call.

# Break with a return value in map
result = [1, 2, 3, 4, 5].map do |num|
  break "Too large!" if num > 3

  num * 2
end
puts result # Output: "Too large!"

# Break with a value in find
number = (1..10).find do |n|
  break n if n > 5 && n.even?
end
puts number # Output: 6

Break in Nested Loops

When using break in nested loops, it only exits the innermost loop. To break from nested loops, you typically need to use a flag or return.

# Break in nested iteration
(1..3).each do |i|
  puts "Outer: #{i}"

  (1..3).each do |j|
    break if j == 2

    puts "  Inner: #{j}"
  end
end
# Output:
# Outer: 1
#   Inner: 1
# Outer: 2
#   Inner: 1
# Outer: 3
#   Inner: 1

# Breaking from nested loops with a flag
found = false
(1..3).each do |i|
  (1..3).each do |j|
    if i * j == 4
      found = true
      break
    end
  end
  break if found
end

The break keyword is essential for controlling loop execution and implementing early exit conditions. It’s particularly useful when you’ve found what you’re looking for and don’t need to continue iterating.