Re: maps: pattern-match absent key?

Björn-Egil Dahlberg <[email protected]> Tue, 18 Feb 2014 21:23:00 +0100

Newsgroups	gmane.comp.lang.erlang.patches
Message-ID	<CAMjYFoOS-dERrOVGYZ2n5EbnVOS-oe1jYJNXicCO_MPY2-yLyg@mail.gmail.com>

Yes, with fail clauses.

f(#{ a := _ }) -> {a,present};
f(_) -> {a,absent}.



2014-02-18 20:55 GMT+01:00 Daniel Goertzen <[email protected]>:

> Is there a way to pattern-match the absence of a key in a map?
>
> Dan.
>
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