I'm trying to build something with custom filters that can be toggled through buttons on a UI. For example

(defn red? [item] (= "red" (:color item)))
(defn large? [item] (= "l" (:size item)))
(defn small? [item] (= "s" (:s item)))

(def selected-options #{red? small?})

(def filter-red (filter red?))
(def filter-large (filter large?))
(def filter-small (filter small?))

(def enabled-filters #{filter-red filter-smal})

(sequence (comp enabled-filters) items)

(sequence (comp filter-red filter-small) items)

I think you want (apply comp enabled-filters)

ah thanks! that worked!

@holmes89 depending on what your bigger task looks like, you could also compose the functions as an arg to one filter, instead of composing the filters

so instead of (comp (filter f) (filter g) (filter h)) you'd have (filter (every-pred f g h))

would that be the same thing with the set of functions? (filter (apply every-pred enabled-filters))? Also is one a better use case than the other? performance?

performance-wise I'd expect one filter to be slightly better than n filters, and every-pred works with apply as expected

I'd choose one or the other based on the larger context - if there are also usages of map / partition etc. it makes sense to compose transducers, if all you need is filtering I think composing a function for a filter is simpler

okay, thanks for answering my questions! My context is just a stupid little app to teach myself. Transducers seemed interesting and I wanted to use it. But this is why I like doing these projects, I now know two different ways based on use cases. Thanks for all the help!

I would recommend you do whatever you find the most readable. The performance difference between these approaches will not be noticeable in almost all cases.

Hello guys, I am a newbie and have basically only understood the syntax and want to start learning more. I wanted to find anyone who's interested in learning this together as a study buddy. This is basically someone who will share resources with each other and meet daily or as much as possible to keep track of the other if they are learning properly. Basically a meetup like partner but in virtual group. If anyone is interested please reply to me in this thread or ping me.

Good morning, everyone. Could anyone help with this? I have issues importing reagent to my setup. I posted everything here: https://ask.clojure.org/index.php/9311/reagent-undefined-in-clj-cljs-setup

I think, I might abandon the idea to host clojure and clojurescript in one codebase. Not only are there no resources on this, I constantly run into issues, even if I try different configurations. This has kept me busy for far too long and the added value doesn’t justify that.

How do I turn this list

[[1 2 3] [4 5 6] [7 8 9]]

[[1 4 7] [2 5 8] [3 6 9]]

@endrebak85 (apply mapv vector x) where x is your list apply splits out your list so it's like [1 2 3] [4 5 6] [7 8 9] mapv is like map but puts the result in a vector (use map if you want the output to be a list) if map is given multiple lists, it takes one from each at a time, so it takes [1 4 7], then [2 5 8] vector just turns them into vectors