Return the flipped version of a number

Question

When a number is shown on a calculator, it's possible to consider what various transformations of that number would look like. For example, on a seven-segment display, 2 is shown like this:

And when flipped horizontally it looks like this:

As such, the mirror image of 2 is 5.

The task in this challenge is to take a single-digit number, and return the number that's its mirror image (if possible). If its mirror image does not look like a number, return the number rotated 180 degrees (if possible). If neither of these are the case, return -1.

Here's the full list of inputs and outputs your program needs to handle:

Input   Output
0       0
1       -1
2       5
3       -1
4       -1
5       2
6       9
7       -1
8       8
9       6

As a code-golf challenge, the shortest code wins!

Answer 1

Haskell - 43 31

43 characters without anything fancy.

f 0=0
f 8=8
f 2=5
f 5=2
f 6=9
f 9=6
f _= -1

Got it down to 31 characters by making it a partial function.

f=([0,-1,5,-1,-1,2,9,-1,8,6]!!)

Answer 2

GolfScript, 15 14

I read the spec again and found that the input must be a string.

"0.5..29.86"\?

To run:

echo -n 2 | ruby golfscript.rb a.gs

Old version(which has integer input):

[0.5..2 9.8 6]?

The newer one(14 byte) is somewhat inspired by the CJam answer by aditsu.

Answer 3

PowerShell - 27

'0 5  29 86'.indexof($args)

Answer 4

Python 2.x - 28

'015..29.86'.find(`input()`)

Answer 5

JavaScript 37 36

alert("0_5__29_86".search(prompt()))

Answer 6

CJam, 20 bytes

q25691347`"5296W"er~

Try it online.

Output

$ for i in {0..9}; { cjam <(echo 'q25691347`"5296W"er~') <<< $i; echo; }
0
-1
5
-1
-1
2
9
-1
8
6

How it works

q          " Read from STDIN. The leaves a string on the stack.            ";
25691347`  " Push the string '25691347'.                                   ";
"5296W"    " Push the string '5296W'.                                      ";
er         " Perform character transliteration.                            ";
~          " Evaluate the result. Examples: '2' returns 2, 'W' returns -1. ";

Answer 7

BEFUNGE 93 - 18 14 20 Bytes

I guess the commentators are right, though Befunge being a 2d language lines are kinda different. Still, in this instant, the commentators are right.

&1g01g-.  
! &  #* )'

Steps:

&

Reads input as a numerical value x, and pushes it on the stack.

1g

Gets the character value c (so, like '!' = 33, or '*' = 42. An empty cell = 32) at position x, 1.

01g-.

Reads the character value of cell 0,1 (33), subtracts it from c, and outputs it as a numerical value.

Answer 8

JavaScript (ECMAScript 6) 25

x=>'1060039097'[x]-(x!=6)

JavaScript (ECMAScript 5) 43

function f(x){return'1060039097'[x]-(x!=6)}

UPDATE: edc65 has suggested a much better technique. toothbrush has suggested a much better language. At this point, my primary contributions are debugging and gumption.

Answer 9

Java - 49

long f(int a){return(0x790a300601L>>(a*4)&15)-1;}

Here, 0x790a300601 is a value stuffed with the desired outputs, with one added to make them positive. The values are stored in nibbles within the value, so a bit of shifting and masking is required to pop them out.

Java - 100 (fun option)

int f(int a){Random r=new Random(0x2000A2F47D6Fl);int b=0;for(;a>=0;a--)b=r.nextInt(11)-1;
return b;}

Not the smallest option, but a bit of fun. I found a random seed that produces the correct values when called X times (where 0 >= X <= 9).

Answer 10

bash 29

tr 1-9 x5xx29x86|sed s/x/-1/g

e.g.

$ echo 0 1 2 3 4 5 6 7 8 9 | tr 1-9 x5xx29x86|sed s/x/-1/g
0 -1 5 -1 -1 2 9 -1 8 6

Answer 11

Kona - 29

This function returns the element x from the array 0 -1 5...

f:{0 -1 5 -1 -1 2 9 -1 8 6@x}

Examples:

> f 2
  5
> f 5
  2
> f 8
  8

Answer 12

JavaScript 36 37 41

alert('0x'+'65b558f5ec'[prompt()]-6)

as ES6 function - 27:

f=v=>'0x'+'65b558f5ec'[v]-6

Answer 13

Sclipting, 11 characters

걄럣뉥밈결⓷方分결剩貶

Finally I have found a Windows computer with Visual Studio installed to build its interpreter. And it has defeated my GolfScript code easily.

It reads 18453063256\11\?/11%( in GolfScript.

Answer 14

J - 28 27 bytes

You know what I like? Simplicity (28 bytes). Note that in J, _1 is negative one (-1).

f=:{&0 _1 5 _1 _1 2 9 _1 8 6

Add a little complexity and you have 27 bytes.

f=:-{&0 2 _3 4 5 3 _3 8 0 3

Example:

   f 2
5
   f 6
9
   f 5
2
...

Answer 15

CJam - 14

Input/output version:

"0 5  29 86"q#

Stack version (assumes the number is on the stack):

[0W5WWY9W8 6]=

Try them at http://cjam.aditsu.net/

Answer 16

Perl, 27 26

Count includes the p flag

y/2569/5296/,s/[1347]/-1/

Usage:

$ echo 7 | perl -pe y/2569/5296/,s/[1347]/-1/
-1

Wait, did Perl just beat J? :)

Answer 17

Marbelous 34 bytes

}0
=6=9=2=5=0=8?0
+3-3+3-3....--

It's not the shortest solution, but it's not the longest either.

How it works

}0 spawns a marble representing the first command line input. This marble drops down the next tick, onto the =6 cell. =6 is a comparison cell, it pushes any marble with value 6 down and all others to the right. This line-up of comparison cells pushes marbles right until they equal a desired value. 0 and 8 just fall through and get printed when tehy fall off the bottom of the board, 6 and 2, and 9 and 5 first get 3 added to them, subtracted from them respectively. If a marble doesn't equal any of the desired values, it lands on the ?0 cell, which turn any marble into a 0 marble¹. This marble then gets decremented and falls off the board.

_{¹ A ?n marble technically turns any marble into a marble between 0 and n. This has the nice side effect that ?0 turns anything into 0.}

Answer 18

MATLAB - 35

I would wrap this in a function with n as the only parameter.

f=[0,-1,5,-1,-1,2,9,-1,8,6];
f(n+1)

35 characters.

Answer 19

ECMAScript 6, 24

f=x=>~-++'0n5nn29n86'[x]

Using normal JavaScript it would be 33:

alert(~-++'0n5nn29n86'[prompt()])

Answer 20

TI-BASIC, 24 22

-1+int(11fPart(11^Ans.0954191904

This encodes the possible outputs in a lookup table stored as a base-11 floating point number; the (N+1)th base-11 digit after the decimal point is extracted from the table to get the value of the inverted digit. In base 11 the number is .106003A097, and the digits of this less one are exactly 0,-1,5,-1,-1,2,9,-1,8,6.

edc65's trick of subtracting one in the case of 6 leads to this 24-byte solution, where ⑩^( is a single one-byte token:

-(Ans≠6)+int(10fPart(.1060039097⑩^(Ans

The string approach is 29 bytes:

-(Ans≠6)+expr(inString("1060039097",Ans+1,1

The array approach (which Ypnpyn also took) is 30 bytes, assuming the number is stored in X:

{1,0,6,0,0,3,10,0,9,7}-1:Ans(X+1

24 -> 22: Removed two extra digits of precision in the magic constant.

Answer 21

C - 47 bytes [was 48 Bytes]

f(i){return(int[]){1,0,6,0,0,3,10,0,9,7}[i]-1;}

To add I/O (which other answers didn't always) for 86 bytes:

main(i){i=(int[]){1,0,6,0,0,3,10,0,9,7}[getchar()-48]-1;i<0?puts("-1"):putchar(i+48);}

Answer 22

Jelly, 14 bytes (non-competing)

ị“-5--29-860”V

Try it online!

Explanation:

ị“-5--29-860”V Takes argument as an integer.
 “-5--29-860”  "-5--29-860" (1-indexed string).
ị              Return the xth char of the string above (y) (x=argument).
             V Eval. - is the same as -1.

Answer 23

05AB1E, 13 bytes (non-competing)

0®5®®Y9®8 6¹@

Try it online!

-3 thanks to Emigna.

Explanation:

0®5®®Y9®8 6¹@ Takes an integer from STDIN.
0®5®®Y9®8 6   Push 0, r=-1, 5, r=-1, r=-1, Y=2, 9, r=-1, 8, 6.
           ¹  Push first input item.
            @ Pop and push the 0-indexed stack item at the respective index.

Answer 24

PHP, 48 39 bytes

Thanks to Jörg Hülsermann

<?=[0,-1,5,-1,-1,2,9,-1,8,6][$argv[1]];

Try it online!

---

Older versions

$m=-1;echo [0,$m,5,$m,$m,2,9,$m,8,6][$argv[1]];

Try it online!

Answer 25

Python - 34

f=lambda n:ord("A@F@@CJ@IG"[n])-65

Answer 26

Java, 58 59

int f(int i){int[]a={1,0,6,0,0,3,10,0,9,7};return a[i]-1;}

OR

int f(int i){return new int[]{1,0,6,0,0,3,10,0,9,7}[i]-1;}

Answer 27

C - 117 108 106 77 76 bytes

a[]={1,0,6,0,0,3,10,0,9,7};main(int c,char**b){printf("%d",a[*b[1]-48]-1);}

Not the best language for golfing, but oh well...
Compile with gcc progname.c -o progname. (Ignore the warnings, or add -include stdio.h to the compile command.)

Usage: ./progname <number>

EDIT

As per @bebe's suggestion, here is an example that takes the input from STDIN instead:

C - 68 51 bytes

main(){printf("%d","106003:097"[getchar()-48]-49);}

Answer 28

JavaScript 42 37

Run it on the console of your browser

alert(~-[1,,6,,,3,10,,9,7][prompt()])

Answer 29

J (24, function)

(the input panel isn't playing nice. Paste the following in a python interpreter and my answer shall be revealed:)

print "f=:{&(_3+3 u:'^C^B^B^E^L^B^K\t')"

Answer 30

Clojure - 36

#(case % 2 5 5 2 6 9 9 6 0 0 8 8 -1)

Answer 31

Python - 92

f=lambda x:x if x in(0,8)else(5if x==2 else(2if x==5 else(6if x==9 else(9if x==6 else -1))))

Usage:

>>> f(2)
5
>>> f(3)
-1

Answer 32

Python - 73 bytes

r=[2,5,2,9,6,9,8,8,0,0]
f=lambda x:-1 if x not in r else r[r.index(x)+1]

Or, for one digit numbers only :

r=[0,-1,5,-1,-1,2,9,-1,8,6]
f=lambda x:r[x]

Answer 33

Java, 75

int f(int i){return i>8?6:i>7?8:i>6?-1:i>5?9:i>4?2:i>2?-1:i>1?5:i>0?-1:0;}

Answer 34

PowerShell 32

(0,-1,5,-1,-1,2,9,-1,8,6)[$args]

Answer 35

F# - 37 bytes

let f n=[0;-1;5;-1;-1;2;9;-1;8;6].[n]

Usage:

> f 2
val it : int = 5
> f 9
val it : int = 6
> f 4
val it : int = -1

Answer 36

TI-BASIC, 35

{1,0,6,0,0,3,10,0,9,7}→L1:L1(X+1)-1

Previous attempt, 42:

6(X=2)+3(X=5)+10(X=6)+9(X=8)+7(X=9)-1+(X=0

Answer 37

C++ 85

Uses nested ternary statements.

int main(){int a;cin>>a;a=(a==2)?5:(a==5?2:(a==6?9:(a==9?6:(a%8==0?a:-1))));cout<<a;}

Answer 38

Bash 26

bc<<<`tr 0-9 106003A097`-1

eg.

for i in {0..9}; do echo $i|
  bc<<<`tr 0-9 106003A097`-1
done
0
-1
5
-1
-1
2
9
-1
8
6

Answer 39

Python3: 47

A very basic implementation, that accepts a input and translates accordingly.

print([0,-1,5,-1,-1,-1,9,-1,8,6][int(input())])

PEP8 is of course sacrificed for the sake of characters. This doesn't come close to rivaling the other Python solution near the top. However, as my first golf, I don't think it's that bad :).

Answer 40

Haskell (full program), 63

main=interact$maybe"-1"(:"").(`lookup`zip"025689""052986").head

Call main, and whatever character your input starts with gets used. Anything that isn't '0', '2', '5', '6', '8', or '9' prints "-1". Unfortunately show wraps characters in single quotes, so the output wouldn't have been consistent, so I had to use (:"") (or (:[])).

Answer 41

Batch - 79

set /aa=%1+1&for /f "tokens=%a%" %%1 in ("0 -1 5 -1 -1 2 9 -1 8 6") do echo>%%1

Used as filename.bat number, output is as a file with the name of the correct number.

Answer 42

Zozotez LISP 87

((:'f(\(k n v)(? k(?(=(a k)n)(a v)(f(d k)n(d v)))'-1)))'(0 2 5 6 8 9)(r)'(0 5 2 9 8 6))

This assumes you start it by seeding one of the REPL supplied so the printing actually is done by Without a driver/REPL you need 3 chars extra:

(p((:'f(\(k n v)(? k(?(=(a k)n)(a v)(f(d k)n(d v)))'-1)))'(0 2 5 6 8 9)(r)'(0 5 2 9 8 6)))

Answer 43

Ruby, 30 bytes

What, no Ruby solution yet?

p'0 5  29 86'.index($*[0])||-1

Takes the input as a command-line argument.

Answer 44

Pyth - 16 bytes

x[ZZ5ZZ2 9Z8 6)Q

Doesn't really count because Pyth was created after this was posted, but it's still pretty neat.

Answer 45

Perl, 22B

perl -pe "y/25690/52960/or$_=-1"

Based off https://codegolf.stackexchange.com/a/32012/19039, but shorter. 1B penalty for -p.

Answer 46

dimwit 24 23 bytes (non-competing)

Edit: removed end bracket, as it is not necessary

Another question that I thought could be good for working on the language with...

R2,5,6,9,[1-7]}5,2,9,6,-1

Explanation:

• R - map replace
• 2,5,7,9,[1-7]} - the searches. Since 2, 5, 6, and 9 are checked first, 1-7 can be used and will simply check if it's 1, 3, 4, or 7. 0 and 8 will therefore stay the same.
• 5,2,9,6,-1 - the replacements. So 2 is replaced by 5, 5 is replaced by 2, etc.

Try it Here

Answer 47

C, 46 bytes

#define f(i)(int[]){1,0,6,0,0,3,10,0,9,7}[i]-1

Answer 48

Turtlèd, 40 bytes (noncompeting)

!.(3'1)(4'1)(1l'-)(2'5l)(5'2)(6'9l)(9'6)

Try it online!

Explanation

!                                          take input
 .                                         write first char of input to cell
  (3'1)                                    if cell is 3, write 1
       (4'1)                               if cell is 4, write 1
            (1l'-)                         If cell is 1, move left and write -
                  (2'5l)                   If cell is 2, write 5 and move left
                        (5'2)              If cell is 5, write 2
                             (6'9l)        If cell is 6, write 9 and move left
                                   (9'6)   If cell is 9, write 6