Morse code translator

Question

Write the shortest program to transform the standard input into Morse code. Characters not in the table should be printed as they are.

Answer 1

C# (213 characters)

I'm sure this wont stand long, but at least I got the technique here first!

class P{static void Main(string[] a){foreach(var t in a[0]){var c="";for(int i=" ETIANMSURWDKGOHVF L PJBXCYZQ  54 3   2       16       7   8 90".IndexOf(t);i>0;i/=2)c="-."[i--%2]+c;System.Console.Write(c+"  ");}}}

And in readable format:

class P
{
    static void Main(string[] a)
    {   
        foreach(var t in a[0])
        {
            var c="";
            for(int i=" ETIANMSURWDKGOHVF L PJBXCYZQ  54 3   2       16       7   8 90".IndexOf(t);i>0;i/=2)c="-."[i--%2]+c;
            System.Console.Write(c+" ");
        }
    }
}

For a brief explanation, the string of characters is a heap in which the left child is a dot and the right child is a dash. To build the letter, you traverse back up and reverse the order.

Answer 2

Golfscript - 74 chars

This answer supports only uppercase and digits. The letters are separated by newlines and words are separated by 2 newlines

{." ETIANMSURWDKGOHVF L PJBXCYZQ"?)"?/'#! 08<>"@))10%=or 2base(;{!45+}%n}%

Analysis

    { }%          as usual works like a map over the array
    .             push a copy of the char onto the stack
    " ETIAN..."   this is a lookup table for the uppercase characters
    ?             like a string.find returns the index of the char in the string
                  or -1 if it is not found (ie it's a digit)
    )             increment that index so E=>2 T=>3 I=>4 etc. notice that if the
                  char is not an uppercase letter or space this is now 0 (False)
    "?/'#!..."    this is a lookup table for the digits. it will be used in the
                  reverse way to the other lookup table.
    @             pull that copy we made of the char to the top of the stack
    ))%10         convert ascii digit to a number by adding 2 and taking mod 10.
                  It's important to do it this way because all the uppercase
                  letters hit this code too, and we need to make sure they fall
                  in the range 0..9 or the next step will fail.
    =             pull the nth char from the string eg "Hello"1= gives "e"
    or            remember if the uppercase lookup fails we have a 0 result, so
                  the digit lookup will be used
    2base         convert to base 2 so E=>[1 0], T=>[1 1], I=>[1 0 0] etc.
    (;            pop the front of the list and throw it away so E=>[0], T=>[1]
    {!45+}%       negate each bit and add 45, this gives ascii value of . and -
    n             newline separates each word. this could be 32 if you wanted to
                  separate the words with spaces for a cost of 1 stroke

Golfscript - 85 chars

This is shorter than my SO answer due to the relaxed requirements here The input must be uppercase/digits and the punctuation characters ".,?"

{." ETIANMSURWDKGOHVF!L!PJBXCYZQ"?)"UsL?/'#! 08<>"@".,?"58,48>+?=or
2base(;{!45+}%n}%

Since the punctuation is not even required here, I may shorten the answer even more

My answer from SO
Golfscript - 107 chars

newline at the end of the input is not supported, so use something like this

echo -n Hello, Codegolfers| ../golfscript.rb morse.gs

Letters are a special case and converted to lowercase and ordered in their binary positions. Everything else is done by a translation table

' '/{{.32|"!etianmsurwdkgohvf!l!pjbxcyzq"?)"UsL?/'#! 08<>"@".,?0123456789"?=or
2base(;>{'.-'\=}%' '}%}%'/'*

Answer 3

tr + sed (347)

tr a-z A-Z | sed 's/0/--O/g;s/1/.-O/g;s/2/.J/g;s/3/..W/g;s/4/.V/g;s/5/.H/g;
 s/6/-.H/g;s/7/-B/g;s/8/-Z/g;s/9/--G/g;s/X/-U/g;s/V/.U/g;s/U/.A/g;
 s/Q/-K/g;s/K/-A/g;s/A/.T/g;s/J/.O/g;s/O/-M/g;s/Y/-W/g;s/W/.M/g;
 s/M/-T/g;s/T/- /g;s/H/.S/g;s/B/-S/g;s/S/.I/g;s/L/.D/g;s/Z/-D/g;
 s/D/-I/g;s/I/.E/g;s/C/-R/g;s/F/.R/g;s/R/.N/g;s/P/.G/g;s/G/-N/g;
 s/N/-E/g;s/E/. /g'

Answer 4

Haskell — 314 292 291 characters

import Data.List
i=intercalate
m=i"       ".map(i" ".map(\c->words".- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -. --- .--. --.- .-. ... - ..- ...- .-- -..- -.-- --.. ----- .---- ..--- ...-- ....- ..... -.... --... ---.. ----."!!(head.findIndices(==c)$['a'..'z']++['0'..'9']))).words

---

A more user readable form:

tbl :: [String]
tbl = words ".- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -. --- .--. --.- .-. ... - ..- ...- .-- -..- -.-- --.. ----- .---- ..--- ...-- ....- ..... -.... --... ---.. ----."

lookupChar :: Char -> String
lookupChar c = tbl !! (fromJust . elemIndex c $ ['a'..'z'] ++ ['0'..'9'])

encWord :: String -> String
encWord = intercalate " " . map lookupChar

encSent :: String -> String
encSent = intercalate "       " . map encWord . words

Sample run:

*Main> m "welcome humans"
".-- . .-.. -.-. --- -- .       .... ..- -- .- -. ..."

There's a single whitespace between two letters, and seven whitespaces between two words.

Answer 5

VB.NET, 233 bytes

Module Module1
 Sub Main(a$())
   For Each c In a(0)
     Dim i = "ETIANMSURWDKGOHVF L PJBXCYZQ  54 3   2       16       7   8 90".IndexOf(c)
     If c <> " " And i >= 0 Then
       Console.Write("{0} ", Morse(i))
     Else
       Console.Write(c)
     End If
   Next
End Sub

Function Morse(i) As String
  Dim b = Math.Log(i) / Math.Log(2)
  Return (From m In MorseSeq(If(Double.IsInfinity(b), 0, b)) Order By m.Length)(i)
End Function

Function MorseSeq(i) As IEnumerable(Of String)
  Return If(i < 0, {}, From n In ".-" From m In MorseSeq(i - 1).DefaultIfEmpty
                       Select n & m)
End Function
End Module

That last function is evil.

edit A couple of improvements.

Function Morse(i) As String
  Return (From m In MorseSeq(i) Order By m.Length)(i)
End Function

Function MorseSeq(i) As IEnumerable(Of String)
  Return If(i=0,{".","-"},From n In".-"From m In MorseSeq(i>>1) Select n & m)
End Function

Answer 6

Postscript (310) (462) (414) (319) including (46) for the table.

Combined numbers and letters with a ternary encoding. 5 ternary digits fit in a byte! This eliminates those silly difference loops, and special-casing numbers entirely.

ASCII85 cuts 1/3 of each table. And simplifying the code (finally!) gets back under 400!

errordict/undefined{pop( )dup 0 4 3 roll put print{}}put<</*{{[exch/@ cvx]cvx 1
index 1 add}forall pop}def/C{<~#:VD<!AP07"A]ga#R),'7h?+2(./s-9e6~>*}def/#{load
exec}/P{print}0{}1{(.)P}2{(---)P}/S{( )P}48<~o'u/0b'A;]L7n~>* 65 C 97 C/@{5{dup
3 mod # S 3 idiv}repeat # S S S}>>begin{(%stdin)(r)file read not{exit}if #}loop

Sample output

Luser Dr00g!
. --- . .     . . ---      . . .      .        . --- .          --- . .      . --- .      --- --- --- --- ---    --- --- --- --- ---    --- --- .      !

Ungolfed and commented. I'm very proud of this one. I feel it's elegant, making the numbers do the work. :)

%!
%Morse Code Translator (Simplified)

%if `load` signals /undefined in /#{load exec},
%  pop --load--,
%  print the char,
%  leave dummy object for `exec` to find
errordict/undefined{pop( )dup 0 4 3 roll put print{}}put

<<
%create int->proc pairs
%from initial int and string values
/*{{[exch/@ cvx]cvx 1 index 1 add}forall pop}def

%the alpha map is applied to Upper and Lower case
/C{<~#:VD<!AP07"A]ga#R),'7h?+2(./s-9e6~>*}def
65 C 97 C

%the number map
48<~o'u/0b'A;]L7n~>*

/#{load exec}  %execute a number
/P{print}

0{}       % 0: nop
1{(.)P}   % 1: '.' dit
2{(---)P} % 2: '---' dah
/S{( )P}  % S: space

%execute a morse sequence, from the table
/@{5{dup 3 mod # S 3 idiv}repeat # S S S}
>>begin

%read and execute each char from stdin
{(%stdin)(r)file read not{exit}if #}loop

The tables (33)+(13)=(46)

Here's how the strings encode the table. Each byte represents a 5-digit ternary number. And the bytes are further encoded in ASCII85 (which postscript can automagically decode).

%The Morse Table in Ternary Encoding
% 3  ^4 ^3 ^2 ^1 ^0
%    81 27  9  3  1                 Dec  Hex  dc ->ASCII85
%   ---------------                 ---  ---  ---
% A            2  1            6+1    7    7  7 256*41+256*50+256*14+
% B      1  1  1  2      27+ 9+3+2   41   29  d85%n85/d85%n85/d85%n85/d85%n85/n
% C      1  2  1  2      27+18+3+2   50   32  2 25 53 35 27  chr(x+33)
% D         1  1  2          9+3+2   14    E  #  :  V  D  <
% E               1              1    1    1
% F      1  2  1  1      27+18+3+1   49   31
% G         1  2  2          9+6+2   17   11  0 32 47 15 22
% H      1  1  1  1      27+ 9+3+1   40   28  !  A  P  0  7
% I            1  1            3+1    4    4
% J      2  2  2  1      54+18+6+1   79   4F
% K         2  1  2         18+3+2   23   17  1 32 60 70 64
% L      1  1  2  1      27+ 9+6+1   43   2B  "  A  ]  g  a
% M            2  2            6+2    8    8
% N            1  2            3+2    5    5
% O         2  2  2         18+6+2   26   1A  2 49 8 11 6
% P      1  2  2  1      27+18+6+1   52   34  #  R )  , '
% Q      2  1  2  2      54+ 9+6+2   71   47
% R         1  2  1          9+6+1   16   10
% S         1  1  1          9+3+1   13    D  22 71 30 10 17
% T               2              2    2    2   7  h  ?  +  2
% U         2  1  1         18+3+1   22   16
% V      2  1  1  1      54+ 9+3+1   67   43
% W         2  2  1         18+6+1   25   19  7 13 14 82 12
% X      2  1  1  2      54+ 9+3+2   68   44  (  .  /  s  -
% Y      2  2  1  2      54+18+3+2   77   4D  77 256*44+256*256*
% Z      1  1  2  2      27+ 9+6+2   44   2C  24 68 21 [23 36]
%                                              9  e  6 [ 8  E] (omit final 2)
% 0   2  2  2  2  2  162+54+18+6+2  242   F2
% 1   2  2  2  2  1  162+54+18+6+1  241   F1
% 2   2  2  2  1  1  162+54+18+3+1  238   EE  78 6 84 14 15
% 3   2  2  1  1  1  162+54+ 9+3+1  229   E5   o '  u  /  0
% 4   2  1  1  1  1  162+27+ 9+3+1  202   CA
% 5   1  1  1  1  1   81+27+ 9+3+1  121   79
% 6   1  1  1  1  2   81+27+ 9+3+2  122   7A  65 6 32 26 60
% 7   1  1  1  2  2   81+27+ 9+6+2  125   7D   b '  A  ;  ]
% 8   1  1  2  2  2   81+27+18+6+2  134   86  134 256*161+256*256*
% 9   1  2  2  2  2   81+54+18+6+2  161   A1  43 22 77 [50 40]
%                                              L  7  n [ S  I] (omit final 2)

Answer 7

Ruby, 161

d=proc{|x|x>1?d[x/2]+".-"[x&1]:' '}
$><<$<.gets.bytes.map{|i|
e=i>64?"-@B4*:68,?5</.7>E20+193ACD"[(i&95)-65]:i>47?"gWOKIHX`df"[i-48]:nil
e ?d[e.ord-40]:i.chr}*''

Encodes each digit into a single char, where 1 is dash, 0 is dot, with a leading 1 as a marker bit (plus an offset to keep it printable. Uses ASCII math to use the input chars as lookup indices.

Answer 8

Python 3, 99 Characters

lambda a:print(*[str(ord('ӆҼzࢤpࢮ࠿yࡊoࡀѡÔÞÝࢭÓӅһѢ'[ord(c)%32])).translate(' -.'*18)for c in a])

Works on upper and lowercase.

Answer 9

Lisp (532 466 chars)

(loop(princ(let((c(read-char)))(case c(#\a".- ")(#\b"-... ")(#\c"-.-. ")(#\d"-.. ")(#\e". ")(#\f"..-. ")(#\g"--. ")(#\h".... ")(#\i".. ")(#\j".--- ")(#\k"-.- ")(#\l".-.. ")(#\m"-- ")(#\n"-. ")(#\o"--- ")(#\p".--. ")(#\q"--.- ")(#\r".-. ")(#\s"... ")(#\t"- ")(#\u"..- ")(#\v"...- ")(#\w".-- ")(#\x"-..- ")(#\y"-.-- ")(#\z"--.. ")(#\1".---- ")(#\2"..--- ")(#\3"...-- ")(#\4"....- ")(#\5"..... ")(#\6"-.... ")(#\7"--... ")(#\8"---.. ")(#\9"----. ")(#\0"----- ")(t c)))))

This encodes lower case letters, and morse code sequences are printed with a trailing space

Answer 10

In Java, 475 characters.

    import java.io.*;class M{public static void main(String[]b){String s,t="-",m=t+t,o=m+t,z="",e=".",i=e+e,p=t+e,a=e+t,n=i+e,c[]={o+m,a+o,i+o,n+m,n+a,n+i,p+n,m+n,o+i,o+p,z,z,z,z,z,z,z,a,t+n,p+p,t+i,e,i+p,m+e,n+e,i,e+o,p+t,a+i,m,p,o,a+p,m+a,e+p,n,t,i+t,n+t,e+m,p+a,p+m,m+i};BufferedReader r=new BufferedReader(new InputStreamReader(System.in));try{s=r.readLine().toUpperCase();for(int j=48;j<91;j++)s=s.replace(z+(char)j,c[j-48]+" ");System.out.println(s);}catch(Exception x){}}}

Translates a-z, A-Z and 0-9.

Edit:

Or in 447 characters, if you don't mind Java throwing an error after the translation.

    import java.io.*;class M{static{String s,t="-",m=t+t,o=m+t,z="",e=".",i=e+e,p=t+e,a=e+t,n=i+e,c[]={o+m,a+o,i+o,n+m,n+a,n+i,p+n,m+n,o+i,o+p,z,z,z,z,z,z,z,a,t+n,p+p,t+i,e,i+p,m+e,n+e,i,e+o,p+t,a+i,m,p,o,a+p,m+a,e+p,n,t,i+t,n+t,e+m,p+a,p+m,m+i};BufferedReader r=new BufferedReader(new InputStreamReader(System.in));try{s=r.readLine().toUpperCase();for(int j=48;j<91;j++)s=s.replace(z+(char)j,c[j-48]+" ");System.out.println(s);}catch(Exception x){}}}

Answer 11

Perl6 (238)

my%h="A.-B-...C-.-.D-..E.F..-.G--.H....I..J.---K-.-L.-..M--N-.O---P.--.Q--.-R.-.S...T-U..-V...-W.--X-..-Y-.--Z--..0-----1.----2..---3...--4....-5.....6-....7--...8---..9----.".split(/<wb>/)[1..72];while$*IN.getc ->$c{print %h{$c.uc}||$c}

Readable version

# Split string on word breaks to create a hash
# I get an extra token at the beginning and end for some reason
# [1..72] is a slice without the extra pieces
my %h = "A.-B-...C-.-.D-..E.F..-.G--.H....I..J.---K-.-L.-..M--N-.O---P.--.Q--.-R.-.S...T-U..-V...-W.--X-..-Y-.--Z--..0-----1.----2..---3...--4....-5.....6-....7--...8---..9----."
    .split(/<wb>/)[1..72];

# For each character in STDIN, print either the looked up value, or itself
while $*IN.getc -> $c {
    print %h{$c.uc} || $c;
}

Answer 12

sed, 159 bytes

s/.*/\L&/
s/[02]/&-/g
s/[89]/&./g
:
s/[b-ilnprsz5-9]/&./g
s/[ajkmoqt-y0-4]/&-/g
y/abcdefghijklmnopqrstuvwxyz0123456789/edri umsewnrttmwkai isadkgojuvhhbzoo/
t

We start by downcasing the entire line (because y can't do case-insensitive conversions); subtract 10 bytes if we are to only handle lower-case input. Then we preprocess the digits 0, 2, 8 and 9 to emit their final symbols.

The loop generates the final symbol for each input character, then translates each character for the next iteration. This is equivalent to walking up the dichotomic search table shown in the Wikipedia article; the digits that needed special treatment can be seen to have parents that are not in our ASCII alphanumerics.

The loop terminates when all characters have reached the terminating space (after 'e' or 't').

For example, the letter k is transformed in three passes:

1. k => k- => n-
2. n- => n.- => t.-
3. t.- => t-.- => -.-

Answer 13

C, 162 160 chars

char M[256] = "_^\\XP@ACGO       &15)\"4+0$>-2'%/6;*(#,8.9=3", v;
main(c) {
  for (;
         c = getchar(), v = M[c + 208 & 255] - 32, ~c;
         putchar(v-1? c : 32))
    for (; v > 1; v /= 2) putchar(".-"[v & 1]);
}

(With non-significant whitespace stripped, no trailing newline)

char M[256]="_^\\XP@ACGO       &15)\"4+0$>-2'%/6;*(#,8.9=3",v;main(c){for(;c=getchar(),v=M[c+208&255]-32,~c;putchar(v-1?c:32))for(;v>1;v/=2)putchar(".-"[v&1]);}

M is a lookup table where the characters' bitpatterns correspond to dots and dashes in the morse code. Characters [0-9A-Z] are decoded to morse using this table (with a space appended after the morse code), other characters are simply passed through unchanged.

Sample run:

HELLO WORLD
.... . .-.. .-.. ---  .-- --- .-. .-.. -.. 
hello world
hello world
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
.- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -. --- .--. --.- .-. ... - ..- ...- .-- -..- -.-- --.. ----- .---- ..--- ...-- ....- ..... -.... --... ---.. ----. 

Answer 14

Powershell, 142 bytes

-join($args|% t*y|%{if($_-match'\w'){for($d='ihfbZJKMQY+mazzy+0;?3,>5:.H7<1/9@E42-6B8CG='[$_-48]-42;$d-1){'.-'[$d%2]
$d=$d-shr1}' '}else{$_}})

Less golfed test script:

$f = {

-join(
    $args|% toCharArray|%{
        if($_-match'\w'){
            for($d='ihfbZJKMQY+mazzy+0;?3,>5:.H7<1/9@E42-6B8CG='[$_-48]-42;$d-1){
                '.-'[$d%2]
                $d=$d-shr1
            }
            ' '
        }else{
            $_
        }
    }
)

}

@(
    ,("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",".- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -. --- .--. --.- .-. ... - ..- ...- .-- -..- -.-- --.. ----- .---- ..--- ...-- ....- ..... -.... --... ---.. ----. ")
    ,("HELLO WORLD", ".... . .-.. .-.. ---  .-- --- .-. .-.. -.. ")
    ,("#$%^&","#$%^&")
) | % {
    $s,$expected = $_
    $result = &$f $s
    "$($result-eq$expected): $result"
}

Output:

True: .- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -. --- .--. --.- .-. ... - ..- ...- .-- -..- -.-- --.. ----- .---- ..--- ...-- ....- ..... -.... --... ---.. ----.
True: .... . .-.. .-.. ---  .-- --- .-. .-.. -..
True: #$%^&

Note: The output contains trailing spaces.

Answer 15

JavaScript (ES6), 184 bytes

For both of these versions, they will put spaces between any characters. Converts 0-9 and a-z(case insensitive) are converted. A space is converted to 3.

s=>s.split("").map(e=>isNaN(d=parseInt(e.toLowerCase(),36))?e:`_OGCA@PX\\^\r\n  `.charCodeAt(d).toString(2).substr(1).split("").map(e=>".-"[e]).join("")).join(" ")

Replace \n with a newline character(0x0a). It is not showing a couple of nonprintable characters because of SE. Going into edit mode shows it.

Here is the hex:

73 3d 3e 73 2e 73 70 6c 69 74 28 22 22 29 2e 6d 61 70 28 65 3d 3e 69 73 4e 61 4e 28 64 3d 70 61 72 73 65 49 6e 74 28 65 2e 74 6f 4c 6f 77 65 72 43 61 73 65 28 29 2c 33 36 29 29 3f 65 3a 60 5f 4f 47 43 41 40 50 58 5c 5c 5e 05 18 1a 0c 02 12 0e 10 04 17 5c 72 14 07 06 0f 16 1d 0a 08 03 09 11 0b 19 1b 1c 60 2e 63 68 61 72 43 6f 64 65 41 74 28 64 29 2e 74 6f 53 74 72 69 6e 67 28 32 29 2e 73 75 62 73 74 72 28 31 29 2e 73 70 6c 69 74 28 22 22 29 2e 6d 61 70 28 65 3d 3e 22 2e 2d 22 5b 65 5d 29 2e 6a 6f 69 6e 28 22 22 29 29 2e 6a 6f 69 6e 28 22 20 22 29

Ungolfed

s=>            //declare anonymous function
s.split("")    //split into array of characters
.map(          //for each character
e=>            //declare anonymous function
 isNaN(        //is the character not in range 0-9a-zA-Z
  d=parseInt(e.toLowerCase(),36)
               //take it as base 36(digits are 0-9a-z) and assign to d
 )?e:          //if outside range, return as is
 `_OGCA@PX\\^\r\n  `
               //table of the morse code as binary as code point with leading 1
 .charCodeAt(d)//get the corresponding code
 .toString(2)  //convert to binary, 0=., 1=-, with an extra 1 bit
 .substr(1)    //remove the extra 1 bit
 .split("")    //split into each bit
 .map(         //for each bit
  e=>          //declare anonymous function
  ".-"         //the corresponding symbol for bits
  [e]          //get it
 )
 .join("")     //join the bits
)
.join(" ")     //join the characters with a space between each character

Readable version, 234 bytes

s=>s.split("").map(e=>isNaN(d=parseInt(e.toLowerCase(),36))?e:[95,79,71,67,65,64,80,88,92,94,5,24,26,12,2,18,14,16,4,23,13,20,7,6,15,22,29,10,8,3,9,17,11,25,27,28][d].toString(2).substr(1).split("").map(e=>".-"[e]).join("")).join(" ")

Ungolfed

s=>            //declare anonymous function
s.split("")    //split into array of characters
.map(          //for each character
e=>            //declare anonymous function
 isNaN(        //is the character not in range 0-9a-zA-Z
  d=parseInt(e.toLowerCase(),36)
               //take it as base 36(digits are 0-9a-z) and assign to d
 )?e:          //if outside range, return as is
 [95,79,71,67,65,64,80,88,92,94,
   5,24,26,12, 2,18,14,16, 4,23,
  13,20, 7, 6,15,22,29,10, 8, 3,
   9,17,11,25,27,28]
               //table of the morse code as binary with leading 1
 [d]           //get the corresponding code
 .toString(2)  //convert to binary, 0=., 1=-, with an extra 1 bit
 .substr(1)    //remove the extra 1 bit
 .split("")    //split into each bit
 .map(         //for each bit
  e=>          //declare anonymous function
  ".-"         //the corresponding symbol for bits
  [e]          //get it
 )
 .join("")     //join the bits
)
.join(" ")     //join the characters with a space between each character

Answer 16

Perl (489 chars)

%c=("A"=>".-","B"=>"-...","C"=>"-.-.","D"=>"-..","E"=>".","F"=>"..-.","G"=>"--.","H"=>"....","I"=>"..","J"=>".---","K"=>"-.-","L"=>".-..","M"=>"--","N"=>"-.","O"=>"---","P"=>".--.","Q"=>"--.-","R"=>".-.","S"=>"...","T"=>"-","U"=>"..-","V"=>"...-","W"=>".--","X"=>"-..-","Y"=>"-.--","Z"=>"--..",1=>".----",2=>"..---",3=>"...--",4=>"..---",5=>".....",6=>"-....",7=>"--...",8=>"---..",9=>"----.",0=>"-----");while(<>){foreach(split(//)){if(exists($c{$_})){printf"%s ",$c{$_}}else{print"$_"}}}

Can be executed via command line like so.

$ perl -e '$CODE' < textfile

Edit: Thanks @tobyodavies for pointing out that my original solution had the translation backwards!

Answer 17

PHP, 474 characters

<?$a=strtoupper(fgets(STDIN));$m=array(65=>".-",66=>"-...",67=>"-.-.",68=>"-..",69=>".",70=>"..-.",71=>"--.",72=>"....",73=>"..",74=>".---",75=>"-.-",76=>".-..",77=>"--",78=>"-.",79=>"---",80=>".--.",81=>"--.-",82=>".-.",83=>"...",84=>"-",85=>"..-",86=>"...-",87=>".--",88=>"-..-",89=>"-.--",90=>"--..",49=>".----",50=>"..---",51=>"...--",52=>"..---",53=>".....",54=>"-....",55=>"--...",56=>"---..",57=>"----.",48=>"-----",32=>" ");while($i++<strlen($a))echo$m[ord($a[$i])];

Its 462 characters if all input is in uppercase:

<?$a=fgets(STDIN);$m=array(65=>".-",66=>"-...",67=>"-.-.",68=>"-..",69=>".",70=>"..-.",71=>"--.",72=>"....",73=>"..",74=>".---",75=>"-.-",76=>".-..",77=>"--",78=>"-.",79=>"---",80=>".--.",81=>"--.-",82=>".-.",83=>"...",84=>"-",85=>"..-",86=>"...-",87=>".--",88=>"-..-",89=>"-.--",90=>"--..",49=>".----",50=>"..---",51=>"...--",52=>"..---",53=>".....",54=>"-....",55=>"--...",56=>"---..",57=>"----.",48=>"-----",32=>" ");while($i++<strlen($a))echo$m[ord($a[$i])];

Answer 18

05AB1E, 81 bytes (Non-competing)

Çvy©58‹i®58-•6V%·,Õo•2B5ôsè}®64›i®64-•4…·]ÑUZ“×\ó$9™¹“ÌLÈÎ%´•3B4ôsè}"012"".- "‡})

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Convert letter patterns to base-3, number patterns to base-2, use zero indexed ascii transliteration to get to periods and hyphens. Does not work on lowercase.

Answer 19

Jelly, 50 bytes

“¤⁵©ḤọḌṄ’B‘s5;“ḄẇɗÞI/QẊṂjỵr’Œ?ḃ2¤ṖṖƊ⁺ị⁾.-;
ØBiịÇ)K

A full program accepting a Python formatted string as a command line argument which prints space delimited output.

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Answer 20

APL(NARS), 71 chars, 142 bytes

{36≥y←⍵⍳⍨⎕A,⎕D:'•-'[0∼⍨⌽(5⍴3)⊤y⊃∊(2⍴256)∘⊤¨⎕AV⍳'ܨ㈍İᄧюᜪࠄᨳ䜏ഁᙂ᥃䴫쩸穼蚠']⋄⍵}

test:

  q←{36≥y←⍵⍳⍨⎕A,⎕D:'•-'[0∼⍨⌽(5⍴3)⊤y⊃∊(2⍴256)∘⊤¨⎕AV⍳'ܨ㈍İᄧюᜪࠄᨳ䜏ഁᙂ᥃䴫쩸穼蚠']⋄⍵}
  q¨'0123456789'
----- •---- ••--- •••-- ••••- ••••• -•••• --••• ---•• ----• 
  q¨"HELLO WORLD"
•••• • •-•• •-•• ---   •-- --- •-• •-•• -••  

each letter is separated from one space, each word would be separated from 3 spaces. The table is build on alphanumeric string ⎕A,⎕D and 16bit characters 'ܨ㈍İᄧюᜪࠄᨳ䜏ഁᙂ᥃䴫쩸穼蚠' they split in 8bit characters each converted in base 3 with reversed digits.

Answer 21

05AB1E, 52 bytes

Ažh«•1Ju&àøΘn₆δβαLmSÂZΘ=+BD1
 ÷ΓùwÒмVšh•… .-ÅвJ#ðδJ‡

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    •1Ju&àøΘn₆δβαLmSÂZΘ=+BD1
    ÷ΓùwÒмVšh•                push compressed number 
              … .-ÅвJ#        convert to custom base " .-"
                      ðδJ     append a space to each morse code
Ažh«                     ‡    transliterate

Answer 22

Vyxal, 56 bytes

ka»ƛ[¬τ*‹∧□C‛Ṡḣ6ƒO⌈=gṫO=D»`-.,`τ⌐Ŀkd5ɾ\.*5ʁṘ-:ƛ‛.-ḂĿ;JĿṄ

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  »...»                               # Base-256 compressed integer
       `-.,`τ⌐                        # Decompressed with the key `-.,`and split on commas
ka            Ŀ                       # Replace letters with those
                 5ɾ\.*                # 1..5 .
                      5ʁṘ-            # With 4..0 - appended 
                          :ƛ‛.-ḂĿ;J   # Make a copy with `.-` swapped
               kd                  Ŀ  # Replace digits with those
                                    Ṅ # Join on spaces and implicitly output

Answer 23

Python 2, 283 274 Bytes

I created a string of alphanumerics such that their placement in the string describes their Morse code representation. Originally I was going to use binary, but 01 would be the same as 1. So I used ternary with - = 1 and . = 2. Thus is character c is at index 1121 in this string, its Morse code representation is --.-.

• To save bytes, I created variables for space, dash and dot.
• Then I hard coded the 'decoder' string using a couple replace statements to reduce whitespace.
• The part of the function converts an index into an array of the ternary digits
• The other part function takes an string and converts each character into Morse code with 3 spaces after letters and 7 (4 extra) between words

q,d,D=" .-"
s=" TE MN AI.OG KD.WR US-.QZ.YC XB- JP  L. F VH---.09  8..7--  6---.1--  2..3  45".replace(D,d*3).replace(d,q*4)
lambda n:''.join(''.join([0,D,d][i]for i in [s.index(c)//3**i%3 for i in range(5)if s.index(c)//3**i!=0][::-1])+q*3 if c!=q else q*4for c in n.upper())

Test Harness

print(f("Hi")=="....   ..   ")
print(f("Hello")=="....   .   .-..   .-..   ---   ")
print(f("Hello World")=="....   .   .-..   .-..   ---       .--   ---   .-.   .-..   -..   ")
print(f("To be or not to be")=="-   ---       -...   .       ---   .-.       -.   ---   -       -   ---       -...   .   ")
print(f("3 14 15")=="...--       .----   ....-       .----   .....   ")

Update

• -9 [16-05-09] Incorporated the ternary calculating function into the main function

[NOTE: There is always trailing white space but white space represents a pause, so I guest that is ok ]

Answer 24

PHP, 157 150 157 bytes

for(;$d=ord($c=$argv[1][$i++]);)echo ctype_alnum($c)?strtr(substr(decbin(ord($d>64?".CTRH@ZF\DUGXABEVOJL?K[ISQP"[$d&31]:"]muy{|ld`^"[$c])-48),1),10,".-"):$c;

takes input from first command line argument. no pause between letters. Run with -nr.

breakdown

for(;$d=ord($c=$argv[1][$i++]);)    # loop through input characters
    echo                                # print ...
    ctype_alnum($c)                     # if char is alphanumeric:
    ?   strtr(
        substr(
        decbin(                         
            ord($d>64                   # 1. map char to char-encoded morse
            ?".CTRH@ZF\DUGXABEVOJL?K[ISQP"[$d&31]
            :"]muy{|ld`^"[$c]
            )-60                        # 2. subtract 60 from ordinal value
        )                               # 3. decbin: convert to base 2
        ,1)                             # 4. substr: skip leading `1`
        ,10,".-")                       # 5. strtr: translate binary digits to dash/dot
    :$c;                                # not alphanumeric: no conversion

Beating JavaScript, Python2, C, Ruby and sed. I´m happy.

4th step: un-merged the mapping to handle lowercase characters without using strtoupper.

previous versions:

fail for lowercase letters; +12 bytes to fix: Replace $argv[1] with strtoupper($argv[1]).

simple string translation, 254 bytes

<?=strtr($argv[1],["-----",".----","..---","...--","....-",".....","-....","--...","---..","----.",A=>".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]);

straight forward: translates the whole string at once, character to morse code.
Save to file to execute or replace <?= with echo and run with -r.

decimal interpretation of morse codes, 184 bytes (-70)

for(;""<$c=$argv[1][$i++];)echo($m=[32,48,56,60,62,63,47,39,35,33,A=>6,23,21,11,3,29,9,31,7,24,10,27,4,5,8,25,18,13,15,2,14,30,12,22,20,19][$c])?strtr(substr(decbin($m),1),10,".-"):$c;

first golfing step: morse codes encoded to binary with an additional leading 1 to preserve leading zeroes. Loops through characters and translates them one by one. Run with -nr.

decimals encoded to character, 157 bytes (-27)

for(;""<$c=$argv[1][$i++];)echo ctype_alnum($c)?strtr(substr(decbin(ord("@"<$c?"CTRH@ZF\DUGXABEVOJL?K[ISQP"[ord($c)-65]:"]muy{|ld`^"[$c])-60),1),10,".-"):$c;

second golfing: added 60 to the decimal value and encoded to character.

merged mapping, 150 bytes (-7)

for(;""<$c=$argv[1][$i++];)echo ctype_alnum($c)?strtr(substr(decbin(ord("]muy{|ld`^8901234CTRH@ZF\DUGXABEVOJL?K[ISQP"[ord($c)-48])-60),1),10,".-"):$c;

third golfing: merged mapping for digits and letters to a single string.

Answer 25

SmileBASIC, 194 190 bytes

INPUT S$WHILE""<S$B=INSTR(" ETIANMSURWDKGOHVFLPJBXCYZQ  54 3   2       16       7   8 90",S$[0])+1IF B THEN S=LOG(B,2)FOR I=0TO S-1?"._"[B-(1<<S)AND S>>I||0];:NEXT?" ";
?SHIFT(S$)*!B;
WEND

Answer 26

JavaScript (Node.js), 143 bytes

s=>[...s].map(t=>`
?/'#! 08<>

	`.charCodeAt(parseInt(t,36)+1).toString(2).slice(1).replace(/./g,e=>'.-'[e])||t).join` `

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