The keys docstring says it returns a sequence, and that's all you get:
it'll do first and next, nothing special about it. The contains? docstring
says it won't do a linear search, so that rules out the result of keys.
(KeySeq just wraps a seq of entries to return the key field.)
What's confusin
No, it should be more explicit.
"If called with a map..."
"If called with a vector..."
Jonathan
On Wed, Aug 7, 2013 at 8:32 PM, Michael Gardner wrote:
> Wouldn't changing "collection" to "associative collection" be enough?
> Though maybe a note about its behavior on vectors would also be good.
Wouldn't changing "collection" to "associative collection" be enough? Though
maybe a note about its behavior on vectors would also be good.
On Aug 7, 2013, at 11:15 , Mark Engelberg wrote:
> Yes, the discussion about contains? has come up before, but there's a new
> aspect to this particular i
Yes, the discussion about contains? has come up before, but there's a new
aspect to this particular instance of the discussion that most of the posts
seem to be ignoring.
The original poster specifically pointed out that his sequence was
constructed by calling the `keys` function on a map:
(keys {
aa the old 'why contains? doesn't work' discussion...even though
it's been a while since it last came up on this list, it must be the
single most popular questions :)
Jim
On 07/08/13 12:24, Goldritter wrote:
In an program I used the result of keys as an argument for a function
which ve
I ran into a similar (in my opinion) issue the other day.
I was working a vector and updating a value at a specific index. Ordering
and performance were important, so it seemed like a good default choice.
(-> [1 2 3] (update-in [1] inc))
Then the code changed a bit, I needed to filter some eleme
On Aug 7, 2013, at 8:22 AM, Jay Fields wrote:
> contains? is possibly poorly named, contains-key? would probably have avoided
> this entire issue.
I'd put it more strongly -- contains? is definitely poorly named, inviting the
assumption that it can be used where you really want "some" with a s
Jay Fields writes:
> For a list, it seems like converting the list to a vectoc (via vec)
> would be a reasonable solution, though I'm sure there's some side
> effect that I haven't considered. Perf would be impacted, but this
> doesn't seem like the kind of thing you'd want to do anyway, so havin
contains? is possibly poorly named, contains-key? would probably have
avoided this entire issue. That said, I'd like to see contains? return
false for things where it doesn't make sense, longs, keywords, etc. For a
list, it seems like converting the list to a vectoc (via vec) would be a
reasonable
That's only obvious if you already know how it works.
Jonathan
On Wed, Aug 7, 2013 at 2:13 PM, Karsten Schmidt wrote:
> The fact, that the docs refer to checking if a "key" is present in the
> collection, should make it obvious which types are supported, no? Only
> vectors, maps and sets have ke
The fact, that the docs refer to checking if a "key" is present in the
collection, should make it obvious which types are supported, no? Only
vectors, maps and sets have keys. Lists and seqs do not. Of course it never
hurts to be more explicit about it...
On 7 Aug 2013 12:49, "Marcus Lindner"
wrot
Marcus Lindner writes:
> But the problem is, that this is not mentioned in the documentation of
> contains? I found so far :(.
Well, it kind of is: Only associative data structures (maps, sets,
records, vectors) have keys, lists and seqs (such as
APersistentMap$KeySeq) don't. I guess the confus
Thanks.
But the problem is, that this is not mentioned in the documentation of
contains? I found so far :(.
I had such a problem a long time ago and remember now which type of
"collection" can be used with contains?. But after a time I will forget
this again and will refer to the documentation. (A
Hi,
`contains?` only works with associative data-structures like maps &
vectors. If you want to find out if a sequence contains a specific
object then you need to use `some` paired with a set as a predicate.
For example:
(some #{3} '(1 2 3 4))
Hope this helps.
~BG
On Wed, Aug 7, 2013 at 4:54
In an program I used the result of keys as an argument for a function which
verifies whether an object is in a passed collection or not.
The result I got was following Exception:
IllegalArgumentException contains? not supported on type:
clojure.lang.APersistentMap$KeySeq clojure.lang.RT.contains
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