[Python] Getting duplicate Python object memory addresses

I noticed something when trying to print map object in Python:

def double(x):
return 2 * x

L = [12, 4, -1]

print(map(double, L))
print(map(double, L))
print(map(double, L))
print(map(double, L))
print(map(double, L))
print(map(double, L))


Here's the result:

<map object at 0x1025f3f40>
<map object at 0x1025f3fd0>
<map object at 0x1025f3f40>
<map object at 0x1025f3fd0>
<map object at 0x1025f3f40>
<map object at 0x1025f3fd0>


It alternates between 2 addresses: 0x1025f3f40 and 0x1025f3fd0.

I have read the post on how Python uses the same address for different instances. However, I thought my code should have reproduced the same result as example #1 rather than example #3 in that post?

Furthermore, I discovered another odd behavior when calling gc.collect() as I suspect it has something to do with garbage collector:

import gc

def double(x):
return 2 * x

L = [12, 4, -1]

print(map(double, L))
gc.collect()
print(map(double, L))
gc.collect()
print(map(double, L))
gc.collect()
print(map(double, L))
gc.collect()
print(map(double, L))
gc.collect()
print(map(double, L))
gc.collect()


In the above code, I added gc.collect() after each print statement. And here's the result:

<map object at 0x100cb3f40>
<map object at 0x100cb3f40>
<map object at 0x100cb2230>
<map object at 0x100cb3f40>
<map object at 0x100cb2230>
<map object at 0x100cb3f40>


It only starts to alternate between 2 addresses after the second print statement! The addresses after the first and the second call are the same.

I wonder what is going on here?

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