Iterators

Question 1

Why do we need “redo” operator?

Answer 1

The redo keyword allows you repeat the last iteration inside the loop.

10.times do |i|
puts “Iteration #{i}”
redo if i > 2
end

# infinity loop
# Iteration 3
# Iteration 3 ...

Question 2

How to write FOR iterator?

Answer 2

for i in [1,2,3] do
p i
end

# 1
# 2
# 3

Question 3

Why do we need “retry” operator?

Answer 3

The retry keyword allows retrying a piece of code in a block.

begin 
  p 'hello'
  raise
rescue
  retry
end

The following code will return ‘hello’ in infinity loop.

Question 4

What is case patter matching?

Answer 4

response = { error: 'Bad Gateway', code: 502 }
case response
in { data: data, code: code }
  puts "Success #{data}, Code: #{code}"
in { error: error, code: code }
  puts "Error: #{error}, Code: #{code}"
end

Error: Bad Gateway, Code: 502