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Strings

Manipulation

Simple substitution cipher

Take a string and return the ROT13 and ROT47 (Check Wikipedia) version of the string.
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab

clojure

(use 'clojure.contrib.cond)

(defn rot13 [s]
(reduce str
(map #(char (let [c (bit-and (int (char %)) 0xDF)]
(+ % (cond-let [i]
(and (>= c (int \A)) (<= c (int \M))) 13
(and (>= c (int \N)) (<= c (int \Z))) -13
true 0))))
(map #(int (char %)) s))))

(defn rot47 [s]
(reduce str
(map #(char (+ % (cond-let [i]
(and (>= % (int \!)) (<= % (int \O))) 47
(and (>= % (int \P)) (<= % (int \~))) -47
true 0)))
(map #(int (char %)) s))))

cpp

#include <algorithm>
#include <iostream>
#include <cctype>
using namespace std;

int rot13(int c) {
if (!isalpha(c)) {
return c;
} else {
char start = islower(c) ? 'a' : 'A';
return ((c - start) + 13) % 26 + start;
}
}

int rot47(int c) {
if (c < 33 || c > 126) {
return c;
} else {
return ((c - 33) + 47) % 94 + 33;
}
}

int main(int argc, char **argv) {
for (int i = 0; i < argc; ++i) {
string original = argv[i];

string rot13enc = original;
transform(original.begin(), original.end(), rot13enc.begin(), rot13);

string rot47enc = original;
transform(original.begin(), original.end(), rot47enc.begin(), rot47);

cout << "original: " << original << endl
<< "rot 13: " << rot13enc << endl
<< "rot 47: " << rot47enc << endl;
}
return 0;
}

erlang

rot13(Str) ->
lists:map(fun(A) ->
if
A >= $A, A =< $Z -> ((A - $A + 13) rem 26) + $A;
A >= $a, A =< $z -> ((A - $a + 13) rem 26) + $a;
true -> A
end
end, Str).

rot47(Str) ->
lists:map(fun(A) ->
if
A >= $!, A =< $~ ->
((A - $! + 47) rem 94) + $!;
true -> A
end
end, Str).

fantom

rot := |Str s, |Int c -> Int| remap -> Str|
{
rs := ""
s.each { rs += remap(it).toChar }
return rs
}

rot13 := |Str s -> Str|
{
rot(s) |Int c -> Int|
{
lc := c.lower
c += (lc >= 'a' && lc <= 'm') ? 13
: ((lc >= 'n' && lc <= 'z') ? -13 : 0)
return c
}
}

rot47 := |Str s -> Str|
{
rot(s) |Int c -> Int|
{
c += (c >= '!' && c <= 'O') ? 47
: ((c >= 'P' && c <= '~') ? -47 : 0)
return c
}
}

s := "Hello World #123"
echo("s=$s")
echo("rot13=${rot13(s)}")
echo("rot47=${rot47(s)}")

fsharp

#light

let rotChar (s:int) (l:int) (h:int) (c:char) =
let charCode = int c
let letterCount = h - l + 1
let newCharCode = (charCode - l + s) % letterCount + l
char newCharCode

let rot13 (text:string) =
let rotChar13 = function
| (c:char) when 'A' <= c && c <= 'Z' -> rotChar 13 (int 'A') (int 'Z') c
| c when 'a' <= c && c <= 'z' -> rotChar 13 (int 'a') (int 'z') c
| c -> c
new string([| for c in text -> rotChar13 c|])

let rot47 (text:string) =
let rotChar47 = function
| ' ' as c -> c
| c -> rotChar 47 (int '!') (int '~') c
new string([| for c in text -> rotChar47 c |])

groovy

char rot13(s) {
char c = s
switch(c) {
case 'A'..'M': case 'a'..'m': return c+13
case 'N'..'Z': case 'n'..'z': return c-13
default : return c
}
}
String.metaClass.rot13 = {
delegate.collect(this.&rot13).join()
}

from = '!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~'
to = 'PQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO'
String.metaClass.rot47 = {
delegate.collect{ int found = from.indexOf(it); found < 0 ? it : to[found] }.join()
}

assert 'Hello World #123'.rot13() == 'Uryyb Jbeyq #123'
assert 'Hello World #123'.rot47() == 'w6==@ (@C=5 R`ab'

haskell

java 1.5

CharArrayWriter rot13 = new CharArrayWriter() ;
for (char c : i ) {
char lc = Character.toLowerCase(c) ;
rot13.append( c += ( (lc >= 'a' && lc <= 'm') ? 13 : ( (lc >= 'n' && lc <= 'z') ? -13 : 0 ) )) ;
}

CharArrayWriter rot47 = new CharArrayWriter() ;
for (char c : i )
rot47.append( c += ( (c >= '!' && c <= 'O') ? 47 : ( (c >= 'P' && c <= '~') ? -47 : 0 ) )) ;

ocaml

let rot_char13 c = match c with
| 'A'..'M' | 'a'..'m' -> Char.chr ((Char.code c) + 13)
| 'N'..'Z' | 'n'..'z' -> Char.chr ((Char.code c) - 13)
| _ -> c

let rot_char47 c = match c with
| '!'..'N' -> Char.chr ((Char.code c) + 47)
| 'O'..'~' -> Char.chr ((Char.code c) - 47)
| _ -> c

let rot f str =
let len = String.length str in
let res = String.create len in
for i = 0 to pred len do
res.[i] <- f str.[i]
done;
(res)

let rot13 = rot rot_char13
let rot47 = rot rot_char47

perl

sub rot13 {
my $str = shift;
$str =~ tr/A-Za-z/N-ZA-Mn-za-m/;
return $str;
}

sub rot47 {
my $str = shift;
$str =~ tr/!-~/P-~!-O/;
return $str;
}

my $string = 'Hello World #123';

print "$string\n";
print rot13($string)."\n";
print rot47($string)."\n";

php (PHP 4 >= 4.2.0, PHP 5) OR (PHP 4, PHP 5)

python

# rot13, readable
rot13_tbl = string.maketrans("ABCDEFGHIJKLMabcdefghijklmNOPQRSTUVWXYZnopqrstuvwxyz", "NOPQRSTUVWXYZnopqrstuvwxyzABCDEFGHIJKLMabcdefghijklm")
string.translate("Hello World #123", rot13_tbl)

#
# "a bad programmer can write bad code in any language"
#

# rot13, "clever"
string.translate("Hello World #123", string.maketrans(string.lowercase+string.uppercase, string.lowercase[13:]+string.lowercase[:13]+string.uppercase[13:]+string.uppercase[:13]))

# rot47, very "clever"
''.join([ord(c) in range(33,127) and chr(((ord(c)-33+47)%(127-33))+33) or c for c in "Hello World #123"])

python

"Hello World #123".encode('rot13')

ruby

rot13 = "Hello World #123".tr!("A-Za-z", "N-ZA-Mn-za-m")
rot47 = "Hello World #123".tr!("\x21-\x7e", "\x50-\x7e\x21-\x4f")

scala

val uppers = 'A' to 'Z'
val lowers = 'a' to 'z'

val alpha13 = (uppers ++ lowers).mkString
val beta13 = ((uppers drop 13) ++ (uppers take 13) ++ (lowers drop 13) ++ (lowers take 13)).mkString

val alpha47 = """!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~"""
val beta47 = """PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO"""

// generic translation function
def rot (alpha: String, beta: String)(c: Char) = if (alpha contains c) beta(alpha indexOf c) else c

// specific translation functions curried with the respective alphabets
val rot13 = rot(alpha13, beta13) _
val rot47 = rot(alpha47, beta47) _

assert(("Hello World #123" map rot13).toString == "Uryyb Jbeyq #123")
assert(("Hello World #123" map rot47).toString == "w6==@ (@C=5 R`ab")

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