On Fri, Jan 23, 2009 at 2:45 PM, Chouser <chou...@gmail.com> wrote:
>
> On Fri, Jan 23, 2009 at 3:39 PM, Justin Johnson
> <ajustinjohn...@gmail.com> wrote:
>> On Fri, Jan 23, 2009 at 2:32 PM, Mark Volkmann <r.mark.volkm...@gmail.com>
>> wrote:
>>>
>>> This must be something I learned months ago and then forgot ...
>>> embarassing!
>>> What's the easiest way to determine if a sequence contains a given value?
>>> I thought there would be something like this: (include? [2 4 7] 4) -> true
>>> That doesn't exist.
>
> Sure it does:
>
> user=> (require 'clojure.contrib.seq-utils)
> nil
> user=> (clojure.contrib.seq-utils/includes? [2 4 7] 4)
> true
>
> :-)
Thanks! It's too bad something this basic isn't in the core.
>>> I know I can do this: (some #{4} [2 4 7])
>>> Having to create a set seems overkill.
>
> It's not! It's beautiful and succinct. And it let's you test for any
> of several values, and then tells you which it found:
>
> user=> (some #{3 4 5} [2 4 7])
> 4
Well ... I agree that it's beautiful and succinct IF you want to test
multiple values. I just think there should be a simpler way to test
for one value that is in the core.
>> user=> (contains? [1 2 3] 1)
>> true
>
> This is doing something different:
>
> user=> (contains? [2 4 7] 7)
> false
>
> That's telling you that the vector has no value at index 7.
Yeah, I just figured that out while you were composing your reply.
Thanks!
--
R. Mark Volkmann
Object Computing, Inc.
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