keys and vals could be any kind of collection. Calling seq will return
either nil or a seq with at least one value. By forcing empty collections
to nil allows the (and ks vs) to work.
That is if keys is [] and vals is [1], then:
(and keys vals) is [1] (a truthy value)
But (seq []) is nil and (
I can't answer for the author, but the answer you gave would be a good
sufficient reason to call seq in those places, yes?
If you create a function zipmap2 that is identical to zipmap, except it
does not have any calls to seq, you get these results:
user=> (zipmap [] [1])
{}
user=> (zipmap2 []
I apologize for this question, because I think it has been asked before,
and yet I can not find the answer.
In the definition of zipmap, what do these 2 lines do?
ks (seq keys)
vs (seq vals)
In particular, what is (seq) doing? Is this to ensure that ks is false if
"keys" is empty? And vs is f
