tqdm progress bar for chained iterables

Question

If I want to combine two iterators in Python, one approach is to use itertools.chain.

For example, if I have two ranges range(50, 100, 10) and range(95, 101), I can get a range [50, 60, 70, 80, 90, 95, 96, 97, 98, 99, 100] with itertools.chain(range(50, 100, 10), range(95, 101)).

tqdm is an extensible progress bar in Python. However, by default it doesn't seem to be able to count the number of items in a itertools.chain expression, even when they are fixed.

One solution is to convert the range to a list. However this approach doesn't scale.

Is there a way to ensure tqdm understands chained iterators?

from tqdm import tqdm
import itertools
import time

# shows progress bar
for i in tqdm(range(50, 100, 10)):
    time.sleep(1)
   
# does not know number of items, does not show full progress bar
for i in tqdm(itertools.chain(range(50, 100, 10), range(95, 101))):
    time.sleep(1)
    
# works, but doesn't scale
my_range = [*itertools.chain(range(50, 100, 10), range(95, 101))]    
for i in tqdm(my_range):
    time.sleep(1)

Answer 1

As of 2023 there is a shorter way by using itertools straightly from tqdm library:

import numpy as np    
from tqdm.contrib.itertools import product

a, b = np.arange(1,10,1), np.arange(20,30,1)

for a1, b1 in product(a,b):
    print(a1, b1)