rubylike_iterator.py

class ri(object):
    def __init__(self, arraylike):
        self.data = arraylike

    def to_a(self):
        return list(self.data)

    def map(self, func):
        return ri(map(func, self.data))

    def filter(self, func):
        return ri(filter(func, self.data))

    def each(self, func):
        self.map(func).to_a()

if __NAME__ == '__MAIN__':
    result = ri([1,2,3,4,5]).map(lambda x: x*3).filter(lambda x: x < 10).to_a()
    print(result) # => [3, 6, 9]