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Comment by eridius | Hacker News Reader

The described issue is even simpler in shell scripting:

  cat file1.txt file2.txt | tr A-Z a-z | sort | uniq > whitelist.txt

Does this mean people aren't going to move from shell scripting to other languages? No, it just means the task is particularly suited to scripting like this, and Python has affordances for scripting.

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Your solution doesn't do the same thing, though. His code doesn't sort.

Sure it does: https://gist.github.com/brettcannon/82c4fe68bac30f4ed653#fil...

Sorry, you are right, I missed that.

Arguably your solution is still different because you sort the input instead of the output, but that's unlikely to matter here.

The only difference is I sort before uniquing, but the python code uniques before sorting. But the result is identical (and in shell scripting, you can't unique without sorting first).

Although FWIW I just checked and the `sort` tool actually has a flag for uniquing during the sort. I don't know if that's portable though.

Yes. Pedantically speaking his solution may be faster for the pathological case of the input consisting almost entirely of duplicates.

It can actually be even simpler:

  sort -u file1.txt file2.txt | tr A-Z a-z > whitelist.txt

You need the -f flag to sort as well to ignore case during the sorting. I don't know how portable the flags to sort are though which is why I didn't bother using them.

This article is evidence that more people need to invest some time in learning shell scripting.

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