Clojurians Log v2

as @dpsutton said you can turn that vector into an (ordered) map by making the key the index [77 76 75 74 73] becomes

{0 77 
 1 76
 2 75
 3 74
 4 73}

hello, could you please tell me where find a tutorial for create an API REST

its great to be here...!😃

Hello I'm using doom emacs and cider for clojure and for some reason, if I run cider on certain directories, emacs will go crazy and use 100% of my cpu, the cider repl will also not open

this happens only on like 1 directory and others projects are fine

Hello Angel This is a nice tutorial that does not make it too complex: https://medium.com/swlh/building-a-rest-api-in-clojure-3a1e1ae096e https://github.com/chris-emerson/rest_demo/blob/master/src/rest_demo/core.clj

2 links there, one is the tutorial, one is the source code of the main core.clj file

if you need any help feel free to ask in the channel ! ^.^

If you haven’t asked there already, you may have a better chance of getting answers in #cider and/or #doom-emacs

thanks

I have a map that I need the keys to be characters like '(' or ';' but I'm not sure what's the best way to make a map with keys like this I currently have it as : {";" "SemiColon"}

Character literals are preceeded by a backslash in Clojure:

{\; "SemiColon" \( "OpeningParenthesis"}

Thanks!! Been a while also 😄

I have json structure like below

{
    "fruit": "Apple",
    "size": "Large",
    "color": "Red"
}
{
    "fruit": "orange",
    "size": "Small",
    "color": "Red"
}

How can I group like below structure

fruit=[Apple, Large]
size=[Large,Small]

(reduce
 (fn [acc {:strs [fruit size]}]
   (-> acc
       (update "fruit" (fnil conj []) fruit)
       (update "size" (fnil conj []) size)))
 {}
 [{...}])

What us :strs ?

destructuring instruction, same as :keys but for string

https://gist.github.com/john2x/e1dca953548bfdfb9844#shortcuts

I got update does noot found , I am using clojure 1.9

I got {f{r{u{it{s{mango orange}}}} after using update-in

@delaguardo ^^

update-in expect to have a sequential path provided as a second argument. I guess you have a string instead. The problem that in clojure string is also sequential data

just use update

it says update not found

oO

could you share your code?

@delaguardo

(reduce
               (fn [acc dt]
                 (-> acc
                     (update "fruits" (fnil conj []) (:fruits dt))
                     (update "size " (fnil conj []) (:size dt ))))
               {}
               data)

oh sorry , i had the code updat eexclude above

I have below code

(def a (interpose "," (get hellovar ":a" )))
(def b (interpose "," (get hellovar ":b" )))
(def c (interpose "," (get hellovar ":c" )))
(def d (interpose "," (get hellovar ":d" )))

I wrote in below way

(defn hellointepe [data]
  (reduce-kv
    (fn [acc k v]
      (assoc acc k (interpose "," v)) )
    {}
    data))

you could use zipmap:

(zipmap (keys hellovar)
        (map (partial interpose ",")
             (vals hellovar)))

but your reduce-kv looks fine, too

I am trying to type cast each value like (map Integer. (get fruts :size)) this giving syntax error at Integer. any reason?

What is the value of (get fruits :size)It has to be a seq.

it is giving 11

It has to be a sequence-like collection, example, vector, list, set...

(map (comp #(Integer/parseInt %) :size) fruits)

if your fruits is something like [{:size "90" :name "apple"} {:name "banana" :size "89"}]

Any one aware of https://github.com/korma/Korma ?

This is a question of personal preferences but in my opinion honeysql is much more “clojure” than korma - https://github.com/seancorfield/honeysql

is there a wrapping library for clojure.string that makes the functions nil-pun?

or if you want to try sql from a higher level of abstraction, there's http://walkable.gitlab.io

That was my production code , so cannot change now

Integer. is not an object that can be passed to map, it is a syntax expanding to calling new on a class and for (IMHO foolish) domain design reasons methods are not first class citizens in java (and thus the JVM), but instead they are special operations on an object. #(Integer. %) takes that constructor invocation and puts it inside a new Object of class clojure.lang.IFn which is an obect with .invoke and .call methods, which is what map expects as its arg.

I seem to remember reading about a project for getting better error messages in Clojure, but I can't seem to find anything when Googling right now. As far as I remember, you could add it to your project and it would look up error messages on a server and give you something more easily understandable. Does anyone know what I'm talking about?

finally, as Indy suggests Integer/parseInt is better than using the Integer constructor Long/parseLong is almost always better than that even because integral literals in clojure code are always Long and on modern computers there are few cases where using an Integer is better

same with Float vs. Double - clojure always prefers the 64 bit type, and down casts to the smaller type for you when it's needed for method call interop

this? https://github.com/bhb/expound

I almost made something like that but before I got motivated enough to flesh it out I just learned the internal classes / methods that keep showing up in stack traces and moved on

as a brand new user I saw Long can't be cast to IFn and got confused and angry, then I went code diving and learned what IFn was and why my code would make that happen, then I started thinking that I could make a guide or program that turned that into a more intuitive message, but before that plan got fleshed out I just developed intuitions for things like IFn and seq coersion and I had other priorities

Thanks @noisesmith, helped

Hi Team, I have a scenario where I have written a function where it calls the database select operation multiple times lets say 10000 times, How can I implement that function, which can be used reduce , map or pmap any suggestion?

can you build the select operation programmatically, at run time? collapsing the 10,000 into 1

or maybe i misunderstand the goal

right, calling a db in a tight loop like that is like opening a file to write each character, then close it again, across a string

it's going to have the correct result but it's never the thing that you want to do in a real app that isn't a toy

I have to call the function multiple times, so using reduce might take more time , so how in clojure we can handle calling same function several time? may be more than >10000

I have passed using In operation for database ( passing multiple argument at same time)

if you want to call the same function multiple times with different arguments, map works

that's what map repeatedly and run! and doseq are for, but it's a bad idea to do this with db calls

But how calling same function multiple times is handled in clojure

it depends on the context

do you have args in a collection? do you have a function ready to take those args? do you need a discrete return value from each call in a new collection?

the answers to those questions are how you decide between map, repeatedly, run!, doseq, iterate, etc. etc.

(defn query-db
  [db lookup-id]
  'data)

(def lookup-ids [1 2 3])

(def db 'db)

(map (partial query-db db) lookup-ids)
;; => (data data data)

but! calling map to get db results means that your db lookups are going to happen in unpredictable places at runtime, and if you already know multiple id's it's always better to do one select to get all of the ids rather than call the db in a loop

there's no one size fits all answer

do you have args in a collection? do you have a function ready to take those args? do you need a discrete return value from each call in a new collection? - Yes

is there any repetition in the calls or repetition in the result you can exploit

I am having trouble using taps. My tap code looks like this:

(defn tap [[type & args]]
  (let [[jobid outtype line] args
        type-color (if (= type :err) red green)
        cmdline (str/join " " [(yellow (str/join " " jobid)) (type-color type) line])]
    (println "------")
    (println cmdline)
    (println "------")
    ))

(add-tap tap)

(tap> [jobid type line])

[[:bwa-map ({:sample "A", :genome "hg38"})]
 :err
 "[main] Real time: 0.853 sec; CPU: 0.646 sec"]

Doing it in the REPL works:

user> (add-tap #(println "----" % "----"))
;; => nil
user> (tap> "hi")
;; => true---- hi ----
"hi"

I'm sure my add-tap was triggered since I added this line above it:

(println "adding tap****************")
(add-tap tap)

@popeyepwr if yes to all of those, use map if it's not io / side effecting / manipulating state, and mapv if it is

it could be your tap function is crashing, I'm not sure you'd see a stack trace if it did

you could put a try / catch with a println in the catch to check

@endrebak85

Clojure 1.10.1
(cmd)user=> (add-tap (fn [& args] (/ 1 0)))
nil
(cmd)user=> (tap> nil)
true
(ins)user=> (add-tap (fn [& args] (try (/ 1 0) (catch Exception e (println "oops!\n" (pr-str e))))))
nil
(cmd)user=> (tap> nil)
true
user=> oops!
 #error {
 :cause "Divide by zero"
 :via
 [{:type java.lang.ArithmeticException
   :message "Divide by zero"
   :at [clojure.lang.Numbers divide "Numbers.java" 188]}]
 :trace
 [[clojure.lang.Numbers divide "Numbers.java" 188]
  [clojure.lang.Numbers divide "Numbers.java" 3901]
  [user$eval142$fn__143 doInvoke "NO_SOURCE_FILE" 1]
  [clojure.lang.RestFn invoke "RestFn.java" 408]
  [clojure.core$fn__8821$fn__8822$fn__8824$fn__8831 invoke "core.clj" 7861]
  [clojure.core$fn__8821$fn__8822$fn__8824 invoke "core.clj" 7860]
  [clojure.lang.AFn run "AFn.java" 22]
  [java.lang.Thread run "Thread.java" 829]]}

@endrebak85 maybe you have “stale” namespaces in your REPL that work, and when you run from the command line, it builds fresh namespaces that don’t work?

I'm actually surprised tap> swallows stack traces silently, that seems like a big gotcha

Or maybe the namespaces don’t load in the same order? I’d try putting (println ">>>> Here goes tap>") in before your tap> line and see if somehow your tap> is executing before the add-tap.

I'm guessing the lack of output from tap> is because of an exception because running the app gives you different data types than the repl experiment

Yeah, the try/catch could be very instructive here.

a simpler way to do it might be (add-tap (fn [& args] (println (try .... (catch Exception e ...))))) then you know you always get a println (unless it's an Error instead of Exception etc.)

Hi, Can someone help me and explain the following behaviour. I evaluate this in the repl and expect to see an error:

(let [foo [1 2 3]]
  (nth foo -1))

Error: No item -1 in vector of length 3

(let [foo [1 2 3]]
  (map-indexed (fn [idx i] (nth foo -1)) foo))

map-indexed is lazy

nothing has tried to read the first element yet

ah okay! That explains it God so simple.

happens to literally every beginner :)

Thank you

so good job getting it out of the way!

(map #({:a %1 :b %2}) [1 2 3] [10 12 12]) (map #(assoc {} :a %1 :b %2) [1 2 3] [10 12 12])

Anyone know why the first line does not work while the second one does?

in the first line you are execing the map as a function, use a do in these cases

like (map #(do {:a %1 :b %2}) [1 2 3] [10 12 12])

or use the hash-map constructor

(map #(hash-map :a %1 :b %2) [1 2 3] [10 12 12])

Is there a way to call out to an api using curl but do so in clojure? Does that make sense? Specifically a command like this:

curl <https://api.openai.com/v1/engines/davinci/completions> \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{"prompt": "This is a test", "max_tokens": 5}'

do you mean make a request to the api from clojure or use curl from clojure?

well I would make a request to an api but I was being lazy in figuring out how to use the java api library. There are no clojure bindings yet as far as I've found

I haven't done that before but it would be good practice

clj-http or http-kit’s client lib.

(we just switched all our HTTP API calls to use the latter since it has no dependencies and a nice, simple async interface)

I actually have those currently open on other tabs so I'm on the right path

so is making a curl request equivalent to a "GET" request?

I also have mdn's http docs up to try and learn some web basics here

curl with -d is going to be a POST

awesome. I'll fiddle with that. the response is going to come back as json. What lib do you recommend there. I just saw an article going over all of them

cheshire

(http/post "<https://api.openai.com/v1/engines/davinci/completions>" {:headers {"content-type" "application/json", "authorization" (str "Bearer " your-api-key)} :body "{\"prompt\": \"This is a test\", \"max_tokens\": 5}"}) — something like that

I recommend org.clojure/data.json since it has no dependencies. Cheshire relies on Jackson which has caused me pain.

(we switched from Cheshire to data.json recently, just before we switched from clj-http to http-kit)

awesome! I will try this out. Thanks folks

Right I think I understand what you mean by execing the map as a function. Thanks both of you for your answers