(def categories [ [ { :id 1 :text "foo" } { :id 2 :text "bar" :ack 5 } ] [
{ :id 3 :age 7 } ] ])
#'user/categories
(update-in categories [1 0] merge { :age 12 :somethingElse 29 })
[[{:text "foo", :id 1} {:text "bar", :ack 5, :id 2}] [{:age 12,
:somethingElse 29, :id 3}]]
On Monday, January 26, 2015 at 8:54:58 AM UTC-6, Erik Price wrote:
>
> 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 <stratto...@gmail.com
> <javascript:>> 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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