Mock RDD in Python: Simulate Spark RDD Lazy Transformations

import random

def mock_rdd(data, num_slices=2):
    """
    A simple simulation of Spark RDD behavior with lazy evaluation,
    transformations, and an action.
    """
    class SimpleRDD:
        def __init__(self, data, num_slices=2):
            self.data = data
            self.num_slices = num_slices
            self.transformations = []

        def map(self, func):
            new_rdd = SimpleRDD(self.data, self.num_slices)
            new_rdd.transformations = self.transformations + [("map", func)]
            return new_rdd

        def filter(self, func):
            new_rdd = SimpleRDD(self.data, self.num_slices)
            new_rdd.transformations = self.transformations + [("filter", func)]
            return new_rdd

        def _slices(self):
            random.shuffle(self.data)
            slice_size = max(1, len(self.data) // self.num_slices)
            return [self.data[i:i + slice_size] for i in range(0, len(self.data), slice_size)]

        def collect(self):
            result = self.data
            for op, func in self.transformations:
                if op == "map":
                    result = [func(x) for x in result]
                elif op == "filter":
                    result = [x for x in result if func(x)]
            return result

    return SimpleRDD(data, num_slices)


if __name__ == "__main__":
    original_list = list(range(1, 11))

    rdd = mock_rdd(original_list, num_slices=3)
    mapped = rdd.map(lambda x: x * 2)
    filtered = mapped.filter(lambda x: x > 10)
    sliced = filtered._slices()

    print("Original:", original_list)
    print("Mapped (x*2):", mapped.collect())
    print("Filtered (x>10):", filtered.collect())
    print("Number of slices:", len(sliced))