Using map with queue.put()?

Question

To load a list into a queue in Python, I found this code snippet which failed to work. No items were added to the queue:

from queue import Queue
my_list = [1,2,3,4,5,6,7,8,9,10]
q = Queue()

# This code doesn't work
map(q.put, my_list)
q.qsize() # Returns zero, which is unexpected

The more verbose solution:

for num in my_list:
    q.put(num)
print(q.qsize())  # returns 10 as expected

works as expected. What am I missing here?

Answer 1

map(q.put, my_list) just returns an iterator. Unless you iterate through it, your queue q wont be populated

>>> q = Queue()
>>> itr = map(q.put, my_list)
>>> q.qsize()
0
>>> _ = list(map(q.put, my_list))
>>> q.qsize()
10