Clojure swapping elements in an input sequence
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How do you swap adjacent elements in an input sequence using clojure.
[10 15 20 25] ---> [15 10 25 20]
[:q :e :g :t :p] ---> [:e :q :t :g :p]
this is how i did it, but pretty sure there are better ways to do it!
(defn switch [s]
(loop [[a b & rest] s
result ]
(if (empty? rest)
(cond
;;empty sequence
(empty? s) result
;;odd sequence
(nil? b) (conj result a)
;;even sequence
:else (conj result b a)
)
(recur rest (conj result b a))))
)
clojure sequence swap
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
add a comment |
0
How do you swap adjacent elements in an input sequence using clojure.
[10 15 20 25] ---> [15 10 25 20]
[:q :e :g :t :p] ---> [:e :q :t :g :p]
this is how i did it, but pretty sure there are better ways to do it!
(defn switch [s]
(loop [[a b & rest] s
result ]
(if (empty? rest)
(cond
;;empty sequence
(empty? s) result
;;odd sequence
(nil? b) (conj result a)
;;even sequence
:else (conj result b a)
)
(recur rest (conj result b a))))
)
clojure sequence swap
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
1
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52
add a comment |
0
0
0
How do you swap adjacent elements in an input sequence using clojure.
[10 15 20 25] ---> [15 10 25 20]
[:q :e :g :t :p] ---> [:e :q :t :g :p]
this is how i did it, but pretty sure there are better ways to do it!
(defn switch [s]
(loop [[a b & rest] s
result ]
(if (empty? rest)
(cond
;;empty sequence
(empty? s) result
;;odd sequence
(nil? b) (conj result a)
;;even sequence
:else (conj result b a)
)
(recur rest (conj result b a))))
)
clojure sequence swap
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
How do you swap adjacent elements in an input sequence using clojure.
[10 15 20 25] ---> [15 10 25 20]
[:q :e :g :t :p] ---> [:e :q :t :g :p]
this is how i did it, but pretty sure there are better ways to do it!
(defn switch [s]
(loop [[a b & rest] s
result ]
(if (empty? rest)
(cond
;;empty sequence
(empty? s) result
;;odd sequence
(nil? b) (conj result a)
;;even sequence
:else (conj result b a)
)
(recur rest (conj result b a))))
)
clojure sequence swap
clojure sequence swap
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
edited Nov 27 '18 at 4:03
Ceylon Boy
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
asked Nov 27 '18 at 2:04
Ceylon BoyCeylon Boy
62
62
1
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52
add a comment |
1
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52
1
1
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52
add a comment |
1 Answer
1
active
oldest
votes
2
(let [A [:q :e :g :t :p]]
(->> A
(partition-all 2)
(mapcat reverse)))
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
1
(map reverse)+flatten==(mapcat reverse)
– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
It's not just more succinct, but more correct.flattenis (almost) never the right answer. Imagine if A were instead defined as[[1 2] [3 4]]. We'd like the result to be[[3 4] [1 2]], but with theflattenversion we would get[3 4 1 2].
– amalloy
Nov 27 '18 at 19:32
add a comment |
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1 Answer
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1 Answer
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(let [A [:q :e :g :t :p]]
(->> A
(partition-all 2)
(mapcat reverse)))
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
1
(map reverse)+flatten==(mapcat reverse)
– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
It's not just more succinct, but more correct.flattenis (almost) never the right answer. Imagine if A were instead defined as[[1 2] [3 4]]. We'd like the result to be[[3 4] [1 2]], but with theflattenversion we would get[3 4 1 2].
– amalloy
Nov 27 '18 at 19:32
add a comment |
2
(let [A [:q :e :g :t :p]]
(->> A
(partition-all 2)
(mapcat reverse)))
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
1
(map reverse)+flatten==(mapcat reverse)
– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
It's not just more succinct, but more correct.flattenis (almost) never the right answer. Imagine if A were instead defined as[[1 2] [3 4]]. We'd like the result to be[[3 4] [1 2]], but with theflattenversion we would get[3 4 1 2].
– amalloy
Nov 27 '18 at 19:32
add a comment |
2
2
2
(let [A [:q :e :g :t :p]]
(->> A
(partition-all 2)
(mapcat reverse)))
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
(let [A [:q :e :g :t :p]]
(->> A
(partition-all 2)
(mapcat reverse)))
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
edited Nov 27 '18 at 6:46
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
answered Nov 27 '18 at 4:24
akondakond
12.6k32849
12.6k32849
1
(map reverse)+flatten==(mapcat reverse)
– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
It's not just more succinct, but more correct.flattenis (almost) never the right answer. Imagine if A were instead defined as[[1 2] [3 4]]. We'd like the result to be[[3 4] [1 2]], but with theflattenversion we would get[3 4 1 2].
– amalloy
Nov 27 '18 at 19:32
add a comment |
1
(map reverse)+flatten==(mapcat reverse)
– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
It's not just more succinct, but more correct.flattenis (almost) never the right answer. Imagine if A were instead defined as[[1 2] [3 4]]. We'd like the result to be[[3 4] [1 2]], but with theflattenversion we would get[3 4 1 2].
– amalloy
Nov 27 '18 at 19:32
1
1
(map reverse) + flatten == (mapcat reverse)– leetwinski
Nov 27 '18 at 6:25
(map reverse) + flatten == (mapcat reverse)– leetwinski
Nov 27 '18 at 6:25
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
Indeed. It is more succinct your way.
– akond
Nov 27 '18 at 6:38
1
1
It's not just more succinct, but more correct.
flatten is (almost) never the right answer. Imagine if A were instead defined as [[1 2] [3 4]]. We'd like the result to be [[3 4] [1 2]], but with the flatten version we would get [3 4 1 2].– amalloy
Nov 27 '18 at 19:32
It's not just more succinct, but more correct.
flatten is (almost) never the right answer. Imagine if A were instead defined as [[1 2] [3 4]]. We'd like the result to be [[3 4] [1 2]], but with the flatten version we would get [3 4 1 2].– amalloy
Nov 27 '18 at 19:32
add a comment |
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1
I'm voting to close this question as off-topic because: It appears to be a simple homework problem.
– Alan Thompson
Nov 27 '18 at 2:41
Show the work you have done so far.
– nakiya
Nov 27 '18 at 2:42
@AlanThompson That is not the official Stack Overflow policy on homework questions. We care about questions that are well asked, and that is independent of whether they are homework. This one looks fine to me, as it clearly defines the desired behavior and shows an attempt. It's even a working attempt, asking for ways to do it better.
– amalloy
Nov 27 '18 at 19:36
The first line was the only thing present when first posted
– Alan Thompson
Nov 27 '18 at 20:52