[erlang-questions] pattern match test operator
Andras Georgy Bekes
Mon Nov 19 14:45:47 CET 2007
> > I can't see when I would want to do a match against
> > a pattern containing only '_'s and if that is true I wouldn't need
> > to match again to retrieve some of the internal terms later on. In
> > this case, it's better to match even the internal structure from
> > the start.
What if you want to filter a list or query a database with two patterns?
You don't (yet) want to retreive the internal terms, just want to have
the elements matching certain patterns.
Instead of writing
[ X || X <- ListOrQLCTable
case X of
You could write this (assume ~= the pattern-match-test operator):
[ X || X <- ListOrQLCTable,
PATTERN1 ~= X orelse PATTERN2 ~= X]
Isn't it nicer?
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