Riddle me Gabe

2019OCT10.rb

def example(a) # function a
  b = [] # b is an empty array
  
  for i in 0..a # for every (i)ndex in the range 0 to a (or 4 in this example)
    b[i] = i # not clear how this works. I think it's a shorthand for .push
             # More importantly, I don't know why you have to assign the position of the index in the array to i
  end # end of loop
  
  return b #return b
end # end of function

example(4) # calls a, loops, pushes 0, 1, 2, 3, 4 into the array b

# => [0, 1, 2, 3, 4]

# 1) write the same thing but replace that logic using ruby each method
# 2) write the same thing but avoid modifying the array, hint: use map
# hint: (0..a).each { |i| ... } and (0..a).map { |i| ... }
# https://www.rubyguides.com/2018/10/ruby-map-method/

# 1) using each

def exampleEach(a)
  b = []
  
  (0..a).each { |i|  
      b[i] = i
    }
  
  return b
  
end

# 2) using map

def exampleEach(a)
  b = []
  
  (0..a).map { |i|
    b[i] = i
    }
end

Feedback

for map there is a an error which doesn't satisfy the condition of the problem, the problem was
2) write the same thing but avoid modifying the array
b used to be [ ] and now it's [0,1,2,3,4]. Let me modify the statement a bit:

• write the same thing but avoid modifying the array, the function needs to return [0,1,2,3,4] but b needs to end up being [ ] (edited)
  you can run irb locally and do the following to verify that:

def exampleEach(a)
  b = []
  
  new_b = (0..a).map { |i|
                   b[i] = i
                }
  puts b
  return new_b
end

Resources

• .each vs. .map and the return
• write the same thing but avoid modifying the array