Reversing of Words

Question

Sona is in her house with her 10 year old daughter. She needs to go to school to bring back another child from school, as school is over at 2 pm. It's hot outside, so she wants to leave her younger child at home.

She gave a bunch of strings to her child to keep her busy while she is gone. She asked her to reverse the words in the string. There are lot of strings, so you need to help her daughter in solving this huge task.

So, given a string that contains words separated by single space, reverse the words in the string. You can assume that no leading or trailing spaces are there.

The string will only contain [a-zA-z ], so you don't need to handle punctuation.

You will be given a string as an input, and you should output a string.

Sample Test Cases:

Input:
Man bites dog 

Output: 
dog bites Man


Input:
The quick brown fox jumps over the lazy dog

Output:
dog lazy the over jumps fox brown quick The


Input:
Hello world

Output:
world Hello

Scoring

This is code-golf. Shortest answer in bytes wins.

Answer 1

Retina, 7 bytes

O$^`\w+

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Match all words (\w+) sort them with sort key empty string (O$) which means they won't get sorted at all, and then reverse their order (^).

Answer 2

Haskell, 21 bytes

unwords.reverse.words

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Answer 3

Python 3, 29 bytes

print(*input().split()[::-1])

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Answer 4

JavaScript (ES6), 31 bytes

s=>s.split` `.reverse().join` `

---

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f=
s=>s.split` `.reverse().join` `
o.innerText=f(i.value="Man bites dog")
oninput=_=>o.innerText=f(i.value)

<input id=i><pre id=o>

Answer 5

Bash + common Linux utilities, 21

printf "$1 "|tac -s\ 

Leaves a trailing space in the output string - not sure if that's OK or not.

Answer 6

Jelly, 3 bytes

ḲṚK

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Explanation:

Ḳ     Splits the input at spaces
Ṛ     Reverses the array
K     Joins the array, using spaces

Answer 7

R, 19 bytes

cat(rev(scan(,'')))

reads the string from stdin. By default, scan reads tokens separated by spaces/newlines, so it reads the words in as a vector. rev reverses, and cat prints the elements with spaces.

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Answer 8

Brachylog, 6 bytes

ṇ₁↔~ṇ₁

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Explanation

ṇ₁        Split on spaces
  ↔       Reverse
   ~ṇ₁    Join with spaces

Note that both "split on spaces" and "join wth spaces" use the same built-in, that is ṇ₁, just used in different "directions".

Answer 9

C#, 58 bytes

using System.Linq;s=>string.Join(" ",s.Split().Reverse());

Answer 10

05AB1E, 4 bytes

#Rðý

Note: Will only work for 2 or more words. +1 byte if this is not OK.

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Answer 11

brainfuck, 74 bytes

,[>++++[<-------->-],]<[>++++[->--------<]+>[[<]>[+>]<]<-[<]>[.>]<[[-]<]<]

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This code creates the number -32 in two different places, but that seems to be fewer bytes than trying to maintain a single -32.

Explanation

,[                        input first character
  >++++[<-------->-]      subtract 32 from current character (so space becomes zero)
,]                        repeat for all characters in input
<                         go to last character of last word
[                         while there are more words to display:
 >++++[->--------<]       create -32 two cells right of last letter
 +>                       increment trailing space cell (1 right of last letter) so the next loop works
 [[<]>[+>]<]              add 32 to all cells in word and trailing space cell
 <-                       subtract the previously added 1 from the trailing space
 [<]>                     move pointer to beginning of word
 [.>]<                    output word (with trailing space)
 [[-]<]                   erase word
 <                        move to last character of previous word
]

Answer 12

Japt, 11 10 7 4 bytes

My first attempt at Japt.

¸w ¸

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• Saved 3 bytes thanks to ETHproductions

---

Explanation

    :Implicit input of string U
¸   :Split on <space>
w   :Reverse
¸   :Join with <space>

---

Please share your Japt tips here.

Answer 13

C, 54 48 bytes

Using arguments as input, 48 bytes

main(c,v)char**v;{while(--c)printf("%s ",v[c]);}

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> ./a.out man bites dog

Using pointers, 84 bytes

f(char*s){char*t=s;while(*t)t++;while(t-s){while(*t>32)t--;*t=0;printf("%s ",t+1);}}

Use

main(){ f("man bites dog"); }

Answer 14

Python 2, 34 bytes

lambda s:' '.join(s.split()[::-1])

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Answer 15

Pyth, 4 bytes

jd_c

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Answer 16

PHP, 47 Bytes

<?=join(" ",array_reverse(explode(" ",$argn)));

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Answer 17

GNU Make, 62 bytes

$(if $1,$(call $0,$(wordlist 2,$(words $1),$1)) $(word 1,$1),)

Answer 18

Röda, 27 25 bytes

2 bytes saved thanks to @fergusq

{[[split()|reverse]&" "]}

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This function takes input from the input stream.

Explanation (outdated)

{[[(_/" ")()|reverse]&" "]}           /* Anonymous function */
   (_/" ")                            /* Pull a value from the stream and split it on spaces */
          ()                          /* Push all the values in the resulting array to the stream */
            |reverse                  /* And reverse it */
  [                 ]                 /* Wrap the result into an array*/
                     &" "             /* Concatenate each of the strings in the array with a space */
 [                       ]            /* And push this result to the output stream */

Answer 19

Mathematica, 35 bytes

StringRiffle@Reverse@StringSplit@#&

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Answer 20

Cubix, 48 bytes

Almost gave up on this one, but finally got there.

oU_;SW;@?ABu>):tS-?;\0$q^s.$;;<$|1osU!(;;...<#(1

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This maps onto a cube with a side length of three as follows

      o U _
      ; S W
      ; @ ?
A B u > ) : t S - ? ; \
0 $ q ^ s . $ ; ; < $ |
1 o s U ! ( ; ; . . . <
      # ( 1
      . . .
      . . .

The general steps are:

• Get all input A and reverse B stack
• Move the negative q to the bottom, add a counter 0 to the stack. bit of jumping around in here.
• Find space/end loop, also puts stack in correct print order.
  • Increment counter ) and fetch the counter item from the stack t
  • Is it a space or EOI S-?
  • Repeat if not
• Print word loop
  • Decrement counter (
  • Exit loop if counter !U is 0
  • Swap s counter with character on stack
  • Print o character and pop it from the stack ;
  • Repeat loop
• Get the length of the stack # and decrement (
• Check ? if 0 and exit @ if it is 0
• Otherwise print a space So clean up ;; and go back to the first loop.

I've skipped a number of superfluous steps, but you can see it Step By Step

Answer 21

CJam, 7 bytes

qS/W%S*

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Explanation

q        e# Read input
 S/      e# Split on spaces
   W%    e# Reverse
     S*  e# Join with spaces

Answer 22

Ohm, 4 bytes

z]Qù

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Explanation

z     Split the input on spaces.
 ]    Dump it onto the stack.
  Q   Reverse the stack.
   ù  Join the stack with spaces. Implicit output.

Answer 23

k, 9 bytes

" "/|" "\

Try it in your browser of the web variety!

     " "\ /split on spaces
    |     /reverse
" "/      /join with spaces

Answer 24

J, 6 bytes

|.&.;:

Try it online! This is reverse (|.) under (&.) words (;:). That is, split sentence into words, reverse it, and join the sentence again.

Answer 25

Java 8, 62 bytes

s->{String r="";for(String x:s.split(" "))r=x+" "+r;return r;}

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Java 7, 77 bytes

String c(String s){String r="";for(String x:s.split(" "))r=x+" "+r;return r;}

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Answer 26

Gema, 29 characters

<W><s>=@set{o;$1 ${o;}}
\Z=$o

Sample run:

bash-4.4$ gema '<W><s>=@set{o;$1 ${o;}};\Z=$o' <<< 'Man bites dog'
dog bites Man 

Answer 27

Java 8, 53 57 bytes

Lambda + Stream API

s->Stream.of(s.split(" ")).reduce("",(a,b)->b+" "+a)

Following Selim suggestion, we just dropped 4 bytes

Answer 28

Perl 6, 14 bytes

{~[R,] .words}

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Expanded:

{              # lambda with implicit param $_

  ~            # stringify following (joins a list using spaces)

   [R,]        # reduce the following using the Reverse meta operator

        .words # call the words method on $_
}

Answer 29

Vim, 20 bytes

:s/ /\r/g|g/^/m0<cr>vGJ

This is shorter than the other vim answer.

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Answer 30

Pyth, 3 bytes

_cw

My first Pyth answer, one byte shorter than @notjagan's answer!

Explained:

 cw # Split the input by space (same as Python's string.split())
_   # Reverses the array
    # Pyth prints implicitly.

Answer 31

TAESGL, 7 bytes

ĴS)Ř)ĴS

Interpreter

Explanation

 ĴS)Ř)ĴS
AĴS)        implicit input "A" split at " "
    Ř)      reversed
      ĴS    joined with " "

Answer 32

Cheddar, 26 bytes

3 bytes thanks to Conor O'Brien

@.split(" ").rev.join(" ")

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Answer 33

AWK, 30 28 bytes

{for(;++i<=NF;)s=$i" "s}$0=s

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Thanks, manatwork, for catching my needless fluff. :)

Answer 34

Lua, 66 42 bytes

for i=#...,1,-1 do
io.write(arg[i],' ')end

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Answer 35

Ruby, 23+1 = 24 bytes bytes

Uses the -p flag.

$_=$_.split.reverse*' '

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Answer 36

Stacked, 17 bytes

' 'split rev' '#`

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#` is "join".

Answer 37

MATL, 5 bytes

YbPZc

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Explanation

    % Implicitly grab input as a string
Yb  % Split it on all of the spaces, yielding a cell array of words
P   % Flip this array
Zc  % Join these words back together with spaces
    % Implicitly display the result

Answer 38

Scala, 37 bytes

s=>s.split(" ").reverse.mkString(" ")

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Answer 39

jq, 27 characters

(23 characters code + 4 characters command line options)

./" "|reverse|join(" ")

Sample run:

bash-4.4$ jq -Rr './" "|reverse|join(" ")' <<< 'Man bites dog'
dog bites Man

On-line test

Answer 40

Vim, 49 42 bytes

:s/.*/\=join(reverse(split(submatch(0))))/

Thank you to @manatwork for feedback

Answer 41

Ruby, 27 24 bytes

thanks to @manatwork

->a{a.split.reverse*" "}

Answer 42

Swift, 116 bytes

var r:(String)->String={return $0.characters.split(separator:" ").map(String.init).reversed().joined(separator:" ")}

You can try it here

Answer 43

Clojure(script), 57 bytes

#(apply str(interpose" "(reverse(re-seq #"[a-zA-Z]+"%))))

Answer 44

J-uby, 23 bytes

:split|:reverse|~:*&' '

Explanation

:split   # split by spaces
|        # then
:reverse # reverse 
|        # then
~:*&' '  # join with spaces

Answer 45

tcl, 18

puts [lreverse $S]

demo

Answer 46

tcl, 11

lreverse ""
          ^
          |
          Put the string you want to test here between the ""

Can be tested on http://www.tutorialspoint.com/execute_tcl_online.php starting the tcl interpreter by typing tclsh. Then type

lreverse "Man bites dog"

%

lreverse "The quick brown fox jumps over the lazy dog"

%

lreverse "Hello world"

Answer 47

Wren, 40 bytes

Fn.new{|a|a.split(" ")[-1..0].join(" ")}

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Explanation

Fn.new{|a|                             } // Anonymous function with the parameter a
          a.split(" ")                   // Split on spaces
                      [-1..0]            // Reverse the array
                             .join(" ")  // Join the array with spaces