CODEWITHSUNDEEP
clojure
pitalig
pitalig

Reputation: 177

Compare map values with clojure

I need to filter a map, but the filter should compare the value with the previous one and the filtered map should have just values that has diferent signal of the previous.

Here is a example:

Map to filter: {:key1 100 :key2 10 :key3 -20 :key4 -10 :key5 10}
Return: {:key3 -20 :key5 10}

Any sugestion of how can I do this?

Upvotes: 0

Views: 1585

Answers (1)

user12341234
user12341234

Reputation: 7223

I might use partition-by which chunks up a sequence based on when the sequence changes value. We can tell partition-by to look at the "signum" of the values, and then only take the first result in each chunk.

(->> {:key1 100 :key2 10 :key3 -20 :key4 -10 :key5 10}
     (partition-by #(Integer/signum (val %)))
     rest
     (map first))

=> ([:key3 -20] [:key5 10])

Upvotes: 2

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