Loops

For ... in

for element in myArray
  statements
end

• Internally resolves to the following:

myArray.each do |element|
  statements
end

While loop

while expr
  statements
end

single-statement while expr

Until loop

until expr
  statements
end

single-statement until expr

Loop

loop {
  statements
}

Each loop

<array>.each block
<range>.each block

• Iterates through each element of the array or range
  

[1, 2, 3].each { |x| puts x }

('a'..'e').each do |x|
  puts x
end

Times loop

<number>.times block

• Iterates from 0 to n - 1

5.times { |x| puts x }

5.times do |x|
  puts x
end

Upto loop

<number>.upto(<number>) block

• Iterates from m to n inclusively
  

3.upto(6) { |x| puts x }

3.upto(6) do |x|
  puts x
end

Jump statements

• next    # Continue on to the next iteration of the loop
• break  # Break from the loop

• redo   # Repeat the current iteration of the loop
• retry   # Restart the loop from the beginning