Python removes negative ranges from dictionaries

Bug report

Example to reproduce:

print({range(16, 1): 0.5, range(32, 16): 0.5})

The expected output:

{range(16, 1): 0.5, range(32, 16): 0.5}

The actual output:

{range(16, 1): 0.5}

However, this seems interesting:

>>> a = {range(16, 1): 1}
>>> a[range(32, 16)] = 2
>>> a
{range(16, 1): 2}

Python removes negative ranges from dictionaries

You misunderstood something. Python doesn't remove anything from dictionary.

hash(range(32, 16)) == hash(range(16, 1))
> True
# And there's need a check for objects equality 
range(32, 16) == range(16, 1)
> True

So, after these checks, Python decides to change the value of key.

Since both are empty ranges...
Thanks for the clarification