Add contains-value? function

[Chemaclass]

🤔 Background

I think it would be practical if we have a function that checks if a value is inside a collection. Similar as the contains? 🤔

🔖 Changes

• Add contains-value? function

[jenshaase]

array_flip only works with string and integer values. It is not working for something like this:

(contains-value? [:a :b] :a)

Also the current implementation is not working for maps:

(contains-value? {:a 1 :b 2} 1) # => error

I would suggest to solve this problem with existing Phel functions only. Maybe the for loop is an option.

[jenshaase]

Isn't the find function basically what you are looking for? Don't know how it behaves on maps, but you can combine it with the values function and it should work.

[Chemaclass]

That's a good idea. Actually changing the function to this helps a lot:

(defn contains-value?
  "Returns true if value is present in the given collection, otherwise returns false."
  [coll val]
  (if (empty? coll)
    false
    (not (nil? (find |(= $ val) coll)))))

And all the tests that I wrote pass, but not these two:

(is (false? (contains-value? (set 1) 2)))
(is (true? (contains-value? (set 1) 1)))

Any idea why are only these two tests failing? 🤔
What do you think about the new implementation of the contains-value? using find, @jenshaase?

[jenshaase]

I would suggest to wrap coll with the values function. This will then also support maps.

(defn contains-value?
  "Returns true if value is present in the given collection, otherwise returns false."
  [coll val]
  (if (empty? coll)
    false
    (not (nil? (find |(= $ val) (values coll))))))

[Chemaclass]

@jenshaase, thanks! Code updated 👌🏻

[jenshaase]

Could you add tests for maps?

[Chemaclass]

Sure thing, @jenshaase. Done.