Crystal error: undefined method 'member?' for Array

Question

I'm attempting to convert some Ruby code to Crystal.

One of my methods is:

def check_and_pop_arg(match : String, args : Array(String))
  result = args.member?(match)
  args.delete_if{|v| v == match}
  return result
end

The crystal compiler does not like the member? method for Array. It seems that methods is also undefined, and I cannot find the API documentation for the Array class in crystal.

1. How do I check for membership?
2. Is there a good source for API documentation that I'm just not finding?

I've tried searching the web, but even using -"crystal reports", I get far too many false positives.

Answer 1

What you looking for is probably includes?. You can find those things in the API docs, in this case Enumerable.

arr = ["a","b","c"]
puts arr.includes? "b"

range1 = (0..10)
puts range1.includes? 6
puts range1.includes? 13

# a possible solution using your code
def check_and_pop_arg(match : String, args : Array(String))
  result = args.includes?(match)
  if result
    args.each_index {|i| if args[i] == match; args.delete_at i end }
  end
  result
end

puts check_and_pop_arg "b", arr
puts arr

Output

% crystal run file.cr
true
true
false
true
["a", "c"]