[Tutor] Possible usage of dict comprehensions

[Mats Wichmann]

On 10/19/20 5:19 PM, Manprit Singh wrote:
> Dear sir ,
> 
> Assume I am using Python 3.7 or later, in which dictionary insertion order
> is maintained. If I want to remove duplicates from a list while maintaining
> the order of its elements, doing like this is a valid and a useful use case
> ?
> 
>>>> l = [2, 4, 5, 3, 4, 5, 2, 1]   # List whose duplicates have to be
> removed
>>>> list({i:None for i in l})
> [2, 4, 5, 3, 1]                   # Resultant list with duplicates removed
> , order preserved

Yes, but note that what you have written exists as the fromkeys() method
already:

list(dict.fromkeys(I))

You can fall back to a dict comprehension if you want the values to not
all be the same object, but since you don't care about the values,
fromkeys is fine.