Many functions that affect keyed collections will work on vectors if you
supply the numeric index as a key.
e
On Monday, January 26, 2015, Josh Stratton <strattonbra...@gmail.com> wrote:
> I'm new to clojure and FP in general. One thing that has always been a
> little confusing for me is working with immutable trees. I have a vector
> of categories, each category containing a vector of items--each one a
> hashmap. In that hashmap I have a bunch of attributes including an
> item-id. Now, assuming I have an item id, what's the easiest way to update
> the appropriate hashmap? I can't use an assoc, I believe, because my data
> is in a vector--not keyed by the id.
>
> What I have been doing is writing a function that maps the categories to
> new categories and then write another function that is called on every item
> and updates it iff the item id matches. This works, but it seems really
> clunky and I'm assuming there's a simpler way to do it.
>
> ; categories is a vector of item vectors, where the item is a hash
> (def categories [ [ { :id 1 :text "foo" } { :id 2 :text "bar" :ack 5 } ] [
> { :id 3 :age 7 } ] ])
>
> Is there a more elegant workflow for updating categories? Let's say I
> want to update item of id 3 with { :age 12 :somethingElse 29 }, what's the
> easiest way to do this?
>
> ; so the return would be
> [ [ { :id 1 :text "foo" } { :id 2 :text "bar" :ack 5 } ] [ { :id 3 :age 12
> :somethingElse 29 } ] ]
>
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