Suggestion: Operator `in` for slices

[Paul Backus]

On Wednesday, 29 December 2021 at 11:26:48 UTC, Ola Fosheim 
Grøstad wrote:
> On Wednesday, 29 December 2021 at 10:53:13 UTC, Ola Fosheim 
> Grøstad wrote:
>> removing
>> changed 4095 : 32768
>> changed 1023 : 8192
>> changed 255 : 2048
>> changed 63 : 512
>> changed 15 : 128
>> changed 3 : 32
>
> To put numbers on this, when deleting a long series of keys the 
> hash table has consistently less than 13% filled slots, and 
> right before shrinking it has 3% filled slots (1024/32768). 
> That is a lot of wasted memory, 97%. Hash tables should not be 
> worse than 75% waste as a rule of thumb.
>
> With such high constant factors O(1) notation is of little 
> value.

Seems like an issue worth filing a bugzilla report about.