Using each_with_index with map

Question

I want to take a array and make it an order list. Currently I'm trying to do it in this way:

r = ["a", "b","c"]
r.each_with_index { |w, index| puts "#{index+1}. #{w}" }.map.to_a
# 1. a
# 2. b
# 3. c
#=> ["a", "b", "c"]

the output should be ["1. a", "2. b", "3. c"].

How do I get the proper output to be the new value for the r array?

Answer 1

a.to_enum.with_index(1).map { |element, index| "#{index}. #{element}" }

or

a.map.with_index(1) { |element, index| "#{index}. #{element}" }

with_index(1) makes the index of the first element 1.

In the first solution the array is converted to an enum, and in the second solution the array is directly mapped.

Answer 2

> => r.each_with_index.map { |w, index| "#{index+1}. #{w}" }

> => ["1. a", "2. b", "3. c"]

Answer 3

You need to map first, then puts:

r = %w[a b c]
r.map.with_index do |w, index|
  "#{index + 1}. #{w}"
end.each do |str|
  puts str
end
#=> ["1. a", "2. b", "3. c"]
# prints:
# 1. a
# 2. b
# 3. c

This is because each (and each_with_index) simply returns the original array.