filter out null values

[Razvan Rotaru]

Hi,

What's the clojure way to filter out null values from a sequence?

I have following code:

(filter identity (map myfun myseq))

Is there a better/faster way?

Thanks,
Razvan

[Phil Hagelberg]

Razvan Rotaru <razvan...@gmail.com> writes:

> (filter identity (map myfun myseq))
>
> Is there a better/faster way?

Not yet, but there's an open ticket for that:

http://dev.clojure.org/jira/browse/CLJ-450

-Phil

[Jonas]

Note that `(filter identity ,,,)` will also remove `false` values:

    => (filter identity [1 2 nil 3 false 4])

    (1 2 3 4)

You could use `remove` instead

    => (remove nil? [1 2 nil 3 false 4])

    (1 2 3 false 4)

Hope that helps!

Jonas

[Mark Engelberg]

(keep my-fun my-seq) does exactly what you want, I believe.

[David Powell]

Hmm, the original suggestion for single-arity filter might pre-date the introduction of remove?

(remove nil? xs)

seems more self-explanatory than:

(filter xs)

-- 

Dave