Optional Parameters with blocks?-CodePudding

# multi_map
# Write a method multi_map that accepts an array, an optional number (n), and a block as arguments. 
# The method should return a new array where each element of the original array is repeatedly run through the block n times. 
# If the number argument is not passed in, then the the elements should be run through the block once.

# Examples
def multi_map(arr, &blc, *n)
    narr = [] 

   
    return narr
end

p multi_map(['pretty', 'cool', 'huh?']) { |s| s   '!'}      # ["pretty!", "cool!", "huh?!"]
p multi_map(['pretty', 'cool', 'huh?'], 1) { |s| s   '!'}   # ["pretty!", "cool!", "huh?!"]
p multi_map(['pretty', 'cool', 'huh?'], 3) { |s| s   '!'}   # ["pretty!!!", "cool!!!", "huh?!!!"]
p multi_map([4, 3, 2, 7], 1) { |num| num * 10 }             # [40, 30, 20, 70]
p multi_map([4, 3, 2, 7], 2) { |num| num * 10 }             # [400, 300, 200, 700]
p multi_map([4, 3, 2, 7], 4) { |num| num * 10 }             # [40000, 30000, 20000, 70000]

I need to make a method that takes an array, optional and a block. I get an error with the arguments being called when I run this skeleton program in rspec. Why is this the case?

CodePudding user response：

Consider the following:

irb(main):010:1* def mm(arr, *n, &blc)
irb(main):011:1*   p arr; n.each(&blc)
irb(main):012:0> end
=> :mm
irb(main):013:0> mm("hello", "world") { |x| puts x }
"hello"
world
=> ["world"]
irb(main):014:0>

You've got the *n and &blc in the wrong order in the parameter list.