oke, one problem I do not see how to solve it

Let's say we have the seq [ 1 [ 2 3] 4]

We first have a 1 and that one can be conj with a acc

Then we have a seq [ 2 3 ] . We have to iterate trougth that one.

But how di I "save" the contents of the 4 . Do I need to use 3 variables acc , rest seq and the rest of the whole seq ?

@roelofw Consider instead that you could concat sequences together -- so if you have a non-sequence element, you can turn it into a sequence by wrapping it in [ ], and if you do have a sequence you can recursively flatten it and then concat it (since it may contain nested sequences).

Is this a 4clojure puzzle? Which one? (so I know exactly what problem you're trying to solve)

@seancorfield This is a 4clojure puzzle and here is the link : http://www.4clojure.com/problem/28

As described im not allowed to use flatten, otherwise the puzzle would be very simple

Since you need to handle deeply nested sequences, you'll need to call your "flatten" function recursively on any vectors or lists but you can do this with mapcat and a function that does what I described above.

Hello, Could you help me - give an example/ tutorial - what is possible with clojure in the NLP area?

(eg. generate english communication from AI)

@seancorfield you mean the part , if it's not a seq turn it into a seq otherwise take all the elements out of it ?

@sb: Google suggests this might be a good starting point for you https://github.com/dakrone/clojure-opennlp/blob/master/README.markdown

Yes, I see that. and the stanford nlp too

For me mainly the question, experience with that

what do you think about, what is possible

@roelofw: if coll? x then recursively call your flatten on it else return [x] -- then your flatten function would just mapcat that logic over the collection. Make sense?

oke, that way

you almost give the code away

@sb: I think your question is too vague. You can do anything with Clojure that you can do with Java libraries, just easier.

@roelofw: I avoided parentheses so it's not code 😆

@seancorfield time to experiment with the code. But I was on the good way when I thought about mapcat

:thumbsup::skin-tone-2:

thanks

@seancorfield Yes, I know. I saw a few really good example with java libraries (like stanford-nlp). I try a few.. and I will see. By the way thanks!

bummer, I see a object here :

(defn my-flatten [s] (mapcat (fn [_ n ]  (if (coll? n) (my-flatten n ) ([n])) s )))

(my-flatten [1 [2 3 ] 4]) 

anyone a tip where I go wrong ?

@roelofw Indent your code properly and you'll probably see 1-2 mistakes

@rauh : You mean something like this :

(defn my-flatten [s] 
    (map (fn [_ n ]  
         (if (coll? n) 
           (my-flatten n ) 
           ([n]))
         s )))

yes, line 5 as my first hint

you mean [x] where I want to convert a number to a vector ?

not exactly

hmm, for me that is line 5

there are more problems in the code

oke, what I try to do is take a item of a seq with map.

When that item n is not a seq then make it a seq

otherwise call the function again so it get flattened with mapcat

that was my idea

As a challenge I have to flatten a deep nested seq without using flatten

I know, I see

but first correct some mistakes

first hint: there is a difference between a and (a)

you still refering to the ([n] ) part ?

yes

Im still confused what you exactly wants

I'm talking about difference between ([n]) vs [n]

So it can be [n] instead of ([n]) ?

yes, question is: do you know why?

because it's crucial

your first solution (with mapcat) works after you correct 3 errors

this is first one

I think ([x]) is a seq containing a vector

no

[x] is a vector with one element

yes

try to make in repl

[1]

([1])

'([1])

([1] 0)

and see what it does or what errors you get

with the second you get this error : ArityException Wrong number of args (0) passed to: PersistentVector clojure.lang.AFn.throwArity (AFn.java:429)

first one works fine and also the thirth one

yes, arity exceptions you get when you try to call function with wrong number of arguments

and the last one works also , gives as output 1

right

I know that after a ( clojure expects a function

yes, exactly!

and that's why ([x]) doesn't produce sequence

except when doing a quote , then you tell clojure to handle it as it is

not exactly, '(a b c) produces list

I think I need to use (seg [x] )

(type '(1 2 ));; => clojure.lang.PersistentList

why? [x] is already a sequence

oke

so one error is solved 🙂

ooops, no it isn't, sorry

😞

but it doesn't matter

mapcat works on vectors too

oke, time for error 2

🙂

any tip where I can find it

You said there are still 2 errors but I cannot see it

yes, first one is parenthesis

I meant second one

@roelofw you never indented your code properly. Use Cursive's help if you can. It'll indent itproperly

third one you get when you call after fixing two first bugs

@rauh : I use the intendation og cursive all the time 😞

ok, then see how many arguments you have for each function and check closing paranthesis

*parantheses

flatten has one. only the given s

map has only 1 , the current item named n

the if then works also on n

aha. the s is on the wrong place. its looks now if it's a part of the anymous function

map needs two parameters, function and collection

oke, it has now . the anymous function and s

if needs three parameters: predicate, value for true and value for false

if

oke, I have now this :

(defn my-flatten [s]
  (map (fn [_ n ]
         (if (coll? n)
           (my-flatten n )
           [n]))
         s )) 

run it

and I now see a arity error on my-flatten

actually not in my-flatten

I see this error : ArityException Wrong number of args (1) passed to: core/my-flatten/fn--1463 clojure.lang.AFn.throwArity (AFn.java:429)

fn--1463 is a key

Which is wierd, my flatten has and must have 1 argument

fn--1463 ss internal anonymous function, and error says that it's called with one (which is wrong) argument

*is

my-flatten has 1 argument on first calling nl. s

it's not about my-flatten

map has also 1 argument the current item

it's about my-flatten/fn--1463

oke, but i cannot see what that function is

you have only one anonymous function inside your my-flatten

so this is this one

yep

That one has only 1 argument. namely n

no

you're wrong

I see two

the other is _ . so it is not important

but it is treated as argument

oke, so at first it has 2 arguments , one who is not important and the n \

I check the if then with n , which looks right to me

"In Clojure, the underscore is used idiomatically to indicate that the argument it identifies is not subsequently used."

map expects a function which has exactly one argument

you've provided function with two

then if n is a seq , I called my_flatten again with n otherwise I put n in a vector

oke, then I confused map with reduce

underscore _ is valid argument name

oke, now n is not known

(defn underscore [_] _)

I have to find another way to use the current item 😞

(underscore "aaa") ;; => "aaa"

show me what you have

got it working, Some code were overwritten

This one :

(defn my-flatten [s]
  (mapcat  (fn [ n ]
         (if (coll? n)
           (my-flatten n )
           [n]))
         s ))


(my-flatten [1 [2 3 ] 4])

works with my own example

with mine as well

Now I hopes it works also with the examples of 4 clojure

(my-flatten [1 [22 [:e] '(1 2 3 [33 33 {:e a}]) 33] [33 33]])
;; => (1 22 :e 1 2 3 33 33 :e a 33 33 33)

@tsulej thanks for the help and patience with me

you're welcome 🙂

one more hint

always appericaited

and time for a late lunch

(defn my-flatten [xs]
  (mapcat 
   #(if (coll? %)
      (my-flatten %)
      [%])
   xs))

#() instead of (fn ...)

aha, instead of fn use the # syntax

just a syntactic sugar

yep

I have to dig into the # , Im still used to use fn

tsulej did you ever work with haskell. I know they use xs for a list/vector

no, I was trying to learn it once but I gave up

this is in use in Scala too (xs is plural for 'x')

oke, thanks

btw https://mwfogleman.github.io/posts/20-12-2014-flatcat.html has a nice discussion on flatten

i'm trying to copy a file to a resource path that's different in development than it is to in production, any ideas?

is there a way to get the current resource path?

usually io/resource takes care of it, but it doesn't work for a file that doesn't exist yet

This has bitten me before. It seems like the resource directory is not present in production

I'm interested in this answer

I think this is a jvm question

it is present, but it's within the jar

so i have a resources directory alongside the jar in production

but in development, it's called dev-resources

any ideas would be great!

@dpsutton I think i've got it

instead of calling io/resource on the none-existent file, i'm doing it on the target directory then amending the new filename

let me know if you want to discuss it further!

Can I somehow flatten a list 1 level. so (( [ 1,2] )) will be ( [ 1,2] ) ?

I cannot find the right method

apply concat

@kauko thanks

@roelofw of course if you know that you're upper level list will only have one item (or at least you're only interested in the first) you can simply use (first xs) where xs is your list

I know. I had to repeat a item several times in a seq so (1 2 ) 3 would be ( 1 1 1 2 2 2 3 3 3 )