Iterators and Generators - Exercise

# Iterators and Generators - Exercise


========================================================================================
# 01. Take Skip

class take_skip:
    def __init__(self, step, count):
        self.step = step
        self.count = count
        self.counter = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self.counter >= self.count:
            raise StopIteration

        result = self.counter * self.step
        self.counter += 1
        return result
========================================================================================

# 02. Dictionary Iterator

class dictionary_iter:
    def __init__(self, kwargs):
        self.kwargs = kwargs
        self.counter = 0

    def __iter__(self):
        return self

    def __next__(self):
        if len(self.kwargs) == 0:
            raise StopIteration

        for count, number in self.kwargs.items():
            result = count,number
            del self.kwargs[count]
            break

        return result
========================================================================================
# 03. Countdown Iterator

class countdown_iterator:
    def __init__(self, num):
        self.num = num

    def __iter__(self):
        return self

    def __next__(self):
        if self.num < 0:
            raise StopIteration

        result = self.num
        self.num -= 1
        return result
========================================================================================

# 04. Sequence Repeat

class sequence_repeat:
    def __init__(self, text, count):
        self.text = text
        self.count = count
        self.index = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self.index == self.count:
            raise StopIteration

        result = self.text[self.index % len(self.text)]
        self.index += 1
        return result
========================================================================================

# 05. Take Halves

def solution():
    def integers():
        num = 1
        while True:
            yield num
            num += 1

    def halves():
        for num in integers():
            yield num / 2

    def take(n, seq):
        return [next(seq) for _ in range(n)]

    return take, halves, integers
========================================================================================

# 06. Fibonacci Generator

def fibonacci():
    n1, n2 = 0, 1

    while True:
        yield n1

        n1, n2 = n2, n1 + n2
========================================================================================

# 07. Reader

def read_next(*args):
    for el in args:
        for sub_el in el:
            yield sub_el
========================================================================================

# 08. Prime Numbers

def get_primes(numbers):
    for number in numbers:
        if number <= 1:
            continue

        for num in range(2,number):
            if number % num == 0:
                break

        else:
            yield number
========================================================================================

# 09. Possible permutations

from itertools import permutations


def possible_permutations(seq):
    for el in permutations(seq):
        yield list(el)