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Jtsummers • today at 1:56 AM • 2 replies • view on HN

You need a way to differentiate the two 5s, that isn't present. If you had a list like:

  L = [(5,foo), (2,bar), (2,baz),...]
And did a:

  SORT(L, key=first) # or however it'd be specified
Then the duplicate 2s would be fine, because they're no longer duplicates, only duplicate keys. But it would still fail if (2,baz) showed up twice in the source and destination even though we've asked for SORT, not UNIQSORT.

Replies

defrost • today at 2:12 AM

In the cases of

  SORT ( 3, 2, 5, 5 ) ->> ( 2, 3, 5, 5 ) and
  SORT ( 3, 2, 5, 5 ) ->> ( 2, 3, 5, 5 )
one or both of those might be incorrect ?

( I'm teasing, perhaps )

defrost • today at 2:28 AM

More seriously,

> You need a way to differentiate the two 5s

As there's no unique filtering or other reduction going on here, there's a permutation chain from input to output.

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