29
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Problem:

You are making a new phone where people can type in specialized phone numbers, for example, 1-800-program, and they would be converted automatically to a usable phone number, like 1-800-7764726 (for the previous example).

Your program will recieve a string if any length with numbers, letters and dashes, and convert all the letters to their corresponding numbers.

Here is a keypad, for reference:

keypad

Rules:

  • Your program will receive a string
  • It will process it and return/print another string
  • Any language is accepted
  • Since it is , the shortest code wins
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2
  • \$\begingroup\$ Should the program handle both upper and lower case letters in the input? \$\endgroup\$ Feb 19, 2014 at 0:38
  • 3
    \$\begingroup\$ @mattnewport - no, assume the variable has been turned into lowercase already \$\endgroup\$
    – TheDoctor
    Feb 19, 2014 at 3:36

41 Answers 41

52
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Bash, 30

Edit: Thank you Doorknob for eliminating 3 chars

tr a-z 22233344455566677778889

Example:

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1
  • 11
    \$\begingroup\$ Can't you remove the last 3 9s? \$\endgroup\$
    – Doorknob
    Feb 19, 2014 at 1:01
17
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C, 83 78 77 65 63 62

main(c){for(;~(c=getchar());putchar(c>96?20-c/122+5*c/16:c));}

http://ideone.com/qMsIFQ

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3
  • 3
    \$\begingroup\$ Nice math. Just wanna say that you can reduce 1 char by assuming EOF is -1 and do ~(c=getchar()) \$\endgroup\$
    – user12205
    Feb 19, 2014 at 8:31
  • \$\begingroup\$ Couldn't you use getch() instead of getchar()? \$\endgroup\$ Feb 19, 2014 at 10:15
  • \$\begingroup\$ Strictly speaking, getch() isn't standard C, as a result I guess it doesn't link in ideone. I tested it in MSVC anyway though and it doesn't really work sadly - as it directly consumes keyboard input there's no way to exit the program, although it does translate what you type on the fly which is kind of neat. \$\endgroup\$ Feb 19, 2014 at 16:05
9
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GolfScript, 24 chars

{.96>{,91,'qx'+-,3/`}*}%

Test input:

0123456789-abcdefghijklmnopqrstuvwxyz

Test output:

0123456789-22233344455566677778889999

Explanation:

  • { }% applies the code between the braces to each character of the input.

  • .96>{ }* executes the code between the inner braces if and only if the ASCII code of the character is greater than 96 (i.e. it is a lowercase letter).

  • The first , turns the character into a list of all characters with lower ASCII codes, and 91,'qx'+- filters out all characters with ASCII codes less than 91, as well as the letters q and x, from the list. Thus, for example, the character a gets turned into the 6-character list [\]^_`, while z gets turned into the 29-character list [\]^_`abcdefghijklmnoprstuvwy.

  • The second , counts the elements remaining in the list, and 3/ divides this count by three (rounding down). Finally, the ` turns the resulting number (in the range 2 – 9) into a string.

Thus, as per spec, hyphens and numbers are left unchanged, while lowercase letters are mapped into numbers according to the reference keypad diagram. The code will actually cleanly pass through all printable ASCII characters except for lowercase letters (which as mapped as described) and the characters {, | and } (which are mapped to the two-character string 10). Non-ASCII 8-bit input will produce all sorts of weird numeric output.

After all this, it's a bit disappointing that this only beats the trivial bash solution by just six chars.

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5
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Javascript - 103 characters

alert(prompt().replace(/[a-z]/g,function(y){y=y.charCodeAt(0)-91;return y>27?9:y>24?8:y>20?7:~~(y/3)}))
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2
  • 1
    \$\begingroup\$ I didn't know you could do that with .replace. Up vote for you! \$\endgroup\$ Jun 11, 2015 at 21:56
  • \$\begingroup\$ You can replace charCodeAt(0) with charCodeAt() and you can use arrow function for function(y)... to save few bytes and for ~~(y/3) you can use y/3|0 \$\endgroup\$
    – Chau Giang
    Sep 20, 2019 at 10:49
3
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Ruby, 75 chars

gets.chars{|c|$><<"22233344455566677778889999#{c}"[[*?a..?z].index(c)||-1]}

Uses the deprecated chars with block, and prints each letter individually with $><<. I also like [[*?a..?z].index(c)||-1]; it grabs the character corresponding to that letter of the alphabet if it's a letter, and the last character (which happens to be the test character unchanged) if not.

Ruby, 43 (or 35) chars

Blatantly stealing from @ace ;)

puts gets.tr'a-z','22233344455566677778889'

Shave off 8 chars if I can run in IRB with the variable s as the string:

s.tr'a-z','22233344455566677778889'
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3
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C++ - 222 chars

Longest solution so far:

#include<iostream>
#include<string>
#define o std::cout<<
int main(){std::string s;std::cin>>s;for(int i=0;i<s.size();i++){int j=s[i]-97;if(j<0)o s[i];if(0<=j&j<15)o 2+j/3;if(14<j&j<19)o 7;if(18<j&j<22)o 8;if(21<j&j<26)o 9;}}
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3
  • 1
    \$\begingroup\$ Lol, I don't think longest solution is the goal here... \$\endgroup\$
    – Danny
    Feb 19, 2014 at 14:36
  • 1
    \$\begingroup\$ @Danny C++ does not lend itself well to code-golf. Java and C# are the only languages that are worse, that I know of (all the classes, object creation, and long names for output...). \$\endgroup\$
    – user10766
    Feb 19, 2014 at 15:53
  • \$\begingroup\$ I know, I just thought it was funny that you mentioned "Longest solution". \$\endgroup\$
    – Danny
    Feb 19, 2014 at 15:55
3
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Frink, 92

A rather verbose language, I know. This checks 8 values instead of 26 without having to type out the compares. Can any of the above "222333444.." solutions be reduced in a similar way?

Using built in structures, 107

co=new OrderedList
co.insertAll[charList["cfilosv{"]]
println[input[""]=~%s/([a-z])/co.binarySearch[$1]+2/eg]

Using a custom recursive function, 92

fn[x,a]:=x<=(charList["cfilosv{"])@a?a+2:fn[x,a+1]
println[input[""]=~%s/([a-z])/fn[$1,0]/eg]
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1
  • 1
    \$\begingroup\$ +1 for reducing the string-translation method to an 8-character search. Nice touch. \$\endgroup\$ Feb 25, 2014 at 1:23
3
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Python 2.7, 66 65


Anakata's Original

for c in raw_input():print'\b'+(`(ord(c)-97)/3+2-(c in('svyz'))`if c>'`'else c),


Further golfed

for c in input():print(ord(c)-91)/3-(c in('svyz'))if c>'`'else c,


I don't have enough reputation to comment on @anakata's answer, so I made a separate post here. I had the same idea (taking the ordinance modulus 3) but couldn't figure out how to print the right numbers for s - z.

Anyways, the golf improvements I made:

  • changed raw_input to input

  • removed the extraneous '\b' and parentheses and single quotes

  • removed the +2 offset and placed that in the original subtraction (97 - (3 * 2) = 91)

Tested with the Python 2.7.6 interpreter. Assumes, per the rules, a string input.

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2
  • \$\begingroup\$ you could also remove the space between the ) and the if \$\endgroup\$
    – Willem
    Mar 13, 2014 at 18:57
  • \$\begingroup\$ You're right. good catch willem \$\endgroup\$
    – zheshishei
    Mar 14, 2014 at 17:24
3
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Scala, 49 48 bytes

_.map(c=>if(c>96)(c/3.2+20).toChar min'9'else c)

Try it online!

Maps abcdefghijklmnopqrstuvwxyz to 22233344455566677778889999 via (c/3.2+20).toChar min'9'

(saved 1 byte thanks to Kevin Cruijssen)

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1
  • 1
    \$\begingroup\$ You can remove the space at min'9' for -1. \$\endgroup\$ Jun 2, 2022 at 9:57
2
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Smalltalk, 79 70

input is s:

s collect:[:c|' 22233344455566677778889999'at:1put:c;at:(($ato:$z)indexOf:c)+1]

probably not a candidate for being shortest - but may be of interest for an old trick to avoid a test for a not-found condition (indexOf: returns 0 in this case). So no special test for letters is needed. Some Smalltalks however, have immutable strings, and we need 4 more chars ("copy").

Oh, a better version, which even deals with immutable strings in 70 chars:

s collect:[:c|c,'22233344455566677778889999'at:(($ato:$z)indexOf:c)+1]
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2
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Mathematica 90

This follows the logic of @ace's solution:

StringReplace[#,Thread[CharacterRange["A","Z"]->Characters@"22233344455566677778889999"]]&

Example

StringReplace[#1,Thread[CharacterRange["A","Z"]-> 
Characters@"22233344455566677778889999"]]&["VI37889"]

8437889

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4
  • \$\begingroup\$ Your arrow character representation isn't accepted by Mma in a copy/paste \$\endgroup\$ Feb 19, 2014 at 3:18
  • \$\begingroup\$ Also,you don't need the 1 in #1:) \$\endgroup\$ Feb 19, 2014 at 3:19
  • \$\begingroup\$ Belisarius, I changed the arrow back and removed the 1. Still 90 char but cut and paste will work. You understand of course the motivation to use the single char arrow. \$\endgroup\$
    – DavidC
    Feb 19, 2014 at 10:36
  • \$\begingroup\$ Been there, done that :) \$\endgroup\$ Feb 19, 2014 at 14:06
2
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Perl, 50

Another obvious copy of Ace's bash answer

($_)=@ARGV;y/a-z/22233344455566677778889999/;print
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1
  • 1
    \$\begingroup\$ This code is working correctly but there's room for improvement. Let's get rid of $ARGV[0] and use -p switch instead which lets you nicely go through each line of stdin. While we're at it, the range in y/// doesn't need to be put in square brackets. We can also get rid of three 9's leaving just one and remove the final semi-colon: -p y/a-z/22233344455566677778889/ There you go, 30 + 1 for -p. Thank you for using Enterprise Chinese Perl Golfing and Optimization Services and have a nice day. \$\endgroup\$ Feb 19, 2014 at 14:11
2
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R, very long but fun

foo <- '1-800-splurghazquieaobuer57'
oof <- unlist(strsplit(foo,''))
#don't count that part - it's input formatting :-) 
digout <- unlist(strsplit('22233344455566677778889999','')) 
oof[oof%in%letters[1:26]] <- unlist(sapply(oof[oof%in%letters[1:26]], function(j) digout[which(letters[1:26]==j)] ))
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2
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k [32 Chars]

{(.Q.a!|,/(4 3 4,5#3)#'|$2+!8)x}

Usage

{(.Q.a!|,/(4 3 4,5#3)#'|$2+!8)x}"stack exchange"
"78225 39242643"
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2
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JavaScript, 85

JavaScript is never going to win the golf wars, but I like it and I wanted to do something different than jump on the @ace bandwagon.

alert(prompt().replace(/[a-z]/g,function(a){for(i=7;a<"dgjmptw{"[i--];);return i+4}))
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2
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PHP, 141

Not the shortest, but more fun:

<?php foreach(str_split($argv[1])as$c){$v=ord($c);if($v>114){$v--;}if($v==121){$v--;}if($v<123&$v>96){echo chr(ceil($v/3+17));}else{echo$c;}}

More readable:

<?php 
foreach (str_split($argv[1]) as $c) {
  $v=ord($c);
  if ($v>114) {$v--;}
  if ($v==121){$v--;}
  if ($v<123 & $v>96){
    echo chr(ceil($v/3+17));
    } else {echo $c;}
}
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1
  • \$\begingroup\$ OP said that the input is already in lowercase, so you can remove the strtolower \$\endgroup\$
    – Einacio
    Feb 20, 2014 at 19:00
2
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Python 2.7, 80

for c in raw_input():print'\b'+(`(ord(c)-97)/3+2-(c in('svyz'))`if c>'`'else c),

I am new to python, so I'm sure there must be a way to golf this even further, it's a different aproach, hope you guys like it, my god, is python pretty!

Run example:

  • input: 01-800-abcdefghijklmnopqrstuvwxyz
  • output: 01-800-22233344455566677778889999
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2
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T-SQL, 216 bytes

I spent quite some time over the past couple of nights painstakingly creating a mathematical sequence function that would round correctly to generate the proper ASCII codes for the numbers from the alphabetical ASCII codes. It had a ridiculous number of decimal places in the coefficients, but it worked.

However, mattnewport's rational approach works in SQL as well, at a much lower cost of bytes, so I am shamelessly scrapping my own math in favor of his. Go up-vote him, it's an elegant solution!

Here's mine:

DECLARE @p VARCHAR(MAX)='';WITH t AS(SELECT ASCII(LEFT(@s,1))c,2 i UNION ALL SELECT ASCII(SUBSTRING(@s,i,1)),i+1FROM t WHERE i<=LEN(@s))SELECT @p=@p+CHAR(CASE WHEN c>96THEN 20-c/122+5*c/16 ELSE c END)FROM t;SELECT @p

This uses a recursive CTE to make an impromptu stack of the characters in the phone number and translate the letters on the fly, then a bit of SQL trickery (SELECT @p=@p+columnValue) to recompose the string from the CTE without requiring another recursion construct.

Output:

DECLARE @s VARCHAR(MAX)='1-800-abcdefghijklmnopqrstuvwxyz'
--above code runs here
1-800-22233344455566677778889999
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2
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05AB1E, 11 bytes

Aā6+žq÷T9:‡

Try it online!

A                 # alphabet: "abcdefghijklmnoqrstuvwxyz"
 ā                # length range: [1..26]
  6+              # add 6 to each: [7..32]
    žq÷           # divide by pi: [2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,7,7,7,7,8,8,8,9,9,9,10]
       T9:        # replace 10 with 9
          ‡       # transliterate the input (a => 2, ..., z => 9)
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0
2
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Vyxal, 14 bytes

ka:ż6+kiḭṪ9JṅĿ

Try it Online!

ka:ż6+kiḭṪ9JṅĿ
ka:            # Push the alphabet twice
   ż           # Length range: [1..26]
    6+         # Add 6: [7..32]
      kiḭ      # Floor divide by pi: [2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,7,7,7,7,8,8,8,9,9,9,10]
         Ṫ9J   # Remove the last item and append 10
            ṅ  # Join by nothing to make a string
             Ŀ # Transliterate the input from the alphabet to this
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1
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PHP, 87

echo str_ireplace(range('a','z'),str_split('22233344455566677778889999'),fgets(STDIN));
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1
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q [38 Chars]

{(.Q.a!"22233344455566677778889999")x}

Inspired by @ace's solution

Example

{(.Q.a!"22233344455566677778889999")x}"stack exchange"
"78225 39242643"
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1
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XQuery, 71

BaseX was used as XQuery processor. $i is input.

translate($i,"abcdefghijklmnopqrstuvwxyz","22233344455566677778889999")

Not the shortest answer, but quite short and very readable.

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1
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Python, very ungolfed

Since everyone is copying ace, i decided to post the code i made up before i submitted the question:

def phonekeypad(text):
    c = ['','','abc','def','ghi','jkl','mno','pqrs','tuv','wxyz']
    st = ""
    for i in list(text):
        a = False
        for t in range(len(c)):
            if i in c[t]:
                st += str(t)
                a=True
        if a == False:
            st += str(i)
    return st
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0
1
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EcmaScript 6 (103 bytes):

i.replace(/[a-z]/g,x=>keys(a='00abc0def0ghi0jkl0mno0pqrs0tuv0wxyz'.split(0)).find(X=>a[X].contains(x)))

Expects i to contain the string.

Try it in any recent version of Firefox. I've not tried Google Chrome.

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2
  • \$\begingroup\$ You can replace split(0) with split`0` \$\endgroup\$
    – LeoDog896
    May 4, 2023 at 13:34
  • \$\begingroup\$ @LeoDog896 True, but that doesn't save any bytes. \$\endgroup\$
    – Toothbrush
    May 12, 2023 at 13:43
1
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Python 3, 121

print("".join((lambda x:"22233344455566677778889999"[ord(x)-97] if ord(x)>96 and ord(x)<123 else x)(i) for i in input()))
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1
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Haskell, 93C

t[]_ a=a
t(b:c)(d:e)a
 |a==b=d
 |True=t c e a
y=map(t['a'..'z']"22233344455566677778889999")

Usage

y "1-800-program"
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1
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C# 140

using System.Linq;class P{static void Main(string[]a){System.Console.Write(string.Concat(a[0].Select(d=>(char)(d>96?20-d/122+5*d/16:d))));}}
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1
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Perl, 54

print map{/[a-y]/?int(5/16*ord)-28:/z/?9:$_}<>=~/./gs

Shoot, @RobHoare still beat me by 4 characters. :)

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1
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C++ (clang), 50 bytes

[](auto&s){for(auto&c:s)c=c>96?20-c/122+5*c/16:c;}

this is a port of mattnewport's C solution.

Try it online!

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