bench.py

import timeit, random
import heapq

random.seed(42)

left = []
right = []

# Create two sorted lists of integers
n = 0
for i in range(100000):
    n += random.randint(1, 10)
    left.append(n)
n = 0
for i in range(100000):
    n += random.randint(1, 10)
    right.append(n)


def merge():
    sortedResult = []
    iLeft = 0
    iRight = 0
    while (len(sortedResult) < (len(left) + len(right))):
        # Append the smaller of left & right's value to `sortedResult`.
        if left[iLeft] < right[iRight]:
            sortedResult.append(left[iLeft])
            iLeft += 1
        else:
            sortedResult.append(right[iRight])
            iRight += 1

        # If one of the pointers has reached the end of its list,
        # put the rest of the other list into `sortedResult`.
        if iLeft == len(left):
            sortedResult.extend(right[iRight:])
            break
        elif iRight == len(right):
            sortedResult.extend(left[iLeft:])
            break

def heapq_merge(_heapq_merge=heapq.merge, _list=list):
    _list(_heapq_merge(left, right))


def appendAndSort():
    sortedResult = left + right
    sortedResult.sort()

def appendAndSorted(_sorted=sorted):
    sortedResult = _sorted(left + right)

n = 100
print(f"{timeit.timeit('merge()', globals=globals(), number=n)=}")
print(f"{timeit.timeit('appendAndSort()', globals=globals(), number=n)=}")
print(f"{timeit.timeit('appendAndSorted()', globals=globals(), number=n)=}")
print(f"{timeit.timeit('heapq_merge()', globals=globals(), number=n)=}")

python3.11 bench.py
timeit.timeit('merge()', globals=globals(), number=n)=4.3249221649894025
timeit.timeit('appendAndSort()', globals=globals(), number=n)=0.3564075309986947
timeit.timeit('appendAndSorted()', globals=globals(), number=n)=0.6240958970010979
timeit.timeit('heapq_merge()', globals=globals(), number=n)=2.1957497320108814