Character encoding issue

Make sure everything is utf8, and your database columns in MySQL are utf8mb4

How can I encoding it I copy SQL from memory and run it in mysql client is ok

Because the act of printing it out and copy and pasting it can change the encoding

Hmm, it may be a bad json encoding instead of character encoding https://stackoverflow.com/questions/44014903/rapidjson-parse-error-invalid-encoding-in-string-207

Yes I found it in JSON from memory

I use clojure.string/replace '\\n' to '\\\n' or replace '\\n' to '\n' It's still get a error

(s/replace (first sql) #"\\n" "\\n")

https://clojuredocs.org/clojure.core/drop-while maybe? (drop-while #(not= % 5) some-seq)

no, i want to effectively call rest 5 times, finding the 5th tail. in common-lisp it is called nth-cdr

I think it's just drop

drop

it is amazing how many small things I forget, not using the language for a while. I was searching for nth-rest and rest-n, and nth-suffix, etc...

nthrest works too

but drop is better if you don't need to eagerly eval the dropped items

https://clojuredocs.org is amazing for lookup something you forget about. you probably remember rest and for this function on clojuredocs there is See Also section with other functions with similar or connected behaviour.

its for a test case so I don't care about laziness. ahh nthrest, not nth-rest. voilà

thanks delaguardo, I did indeed glance quickly through the doc of rest, mostly at the examples, while also searching for prefix, suffix, etc. didn't get all the way to the see-also section.

does the search field in clojuredocs search only function names, or does it search the text as well? its notable that the doc for nthrest does not contain the word "suffix"

neither does the doc for drop.

maybe its due to drop being lazy and suffix could imply eagerness?

naaaa, lazy suffix is quite easy to understand.

@U010VP3UY9X search field on clojuredocs is only for function name. but See Also section does contain docstrings for other functions as well. 1. you wanted a function with some extended behaviour for the rest function 2. lookup rest on clojuredocs, that will give you this page - https://clojuredocs.org/clojure.core/rest 3. Inside of See Also right after examples there are links to drop , nthrest , nthnext 4. and for drop the docstring say “Returns a lazy sequence of all but the first n items in coll.” which sounds to me exactly as you describe what you was looking for. Clojure has it own “standard library” which doesn’t have to be similar to anything you previously had to deal with. This is why there is no mention of “suffix” anywhere.

would be nice if the search, also searched the content (or optionally so). That way someone (anyone) could just add a helpful example containing the word suffix, and problem solved. It is nice that clojuredocs already alows users to add helpful examples.

for example, in the reduce doc there's a helpful example which reminds me of the order of the arguments to the client function [acc item] rather than [item acc] . I use that example often actually.

clojure.repl/find-docs searches docstrings (and can take a regex)

You might try https://clojure.org/api/cheatsheet. Find the right section, in this case “Seq in, Seq out “, then explore Tail-items rest nthrest next fnext nnext drop drop-while take-last for

https://clojuredocs.org/clojure.java.io/copy could work here

also the error could be due the input-stream not being open?

(let [long-string "The rain in spain falls mainly on the plains"
        ranges #{[5 8] [5 15] [2 5]}]
    (mapv (comp clojure.string/upper-case (partial apply subs long-string)) ranges))

repeated uses of str will murder performance. You’ll really need a StringBuilder

Maybe something like this?:

(let [to-uppercase? (fn [n uppercase-ranges] (some #(some #{n} (apply range %)) uppercase-ranges))]
  (->> "Aliquam erat volutpat. Nunc eleifend leo vitae magna. In id erat non orci commodo lobortis. Proin neque massa, cursus ut, gravida ut, lobortis eget, lacus."
       (map-indexed (fn [idx char]
                      (if (to-uppercase? idx #{[0 7] [13 21]})
                        (Character/toUpperCase char)
                        char)))
       (apply str)))

The strings I'm dealing with are quite long, so efficiency is definitely a consideration.

You might look into a rope datastructure that can handle changes in the string without continually rebuilding the entire string

I'm a little surprised this isn't part of one of the string manipulation libraries like https://github.com/funcool/cuerdas or https://github.com/expez/superstring.

@U11BV7MTK thanks for that tip. I'll give https://github.com/IGJoshua/ropes/blob/master/src/clj/ropes/core.clj a try

profile it against a reduce. but in general a rope should be better. But who knows with the immutability. Maybe finding a mutable one or perhaps that offers a transient version?

Noted.. will do. Thanks everyone for the input.

any rule of thumb for when a dev should think of this type of issue (performance of strings)