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:

enter image description here

And when flipped horizontally it looks like this:

enter image description here

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!

I disagree with your last point -- a 1 on a 7 segment display would simply be flipped to the other side, so 1 should nap to 1. — Jwosty, Commented Jun 17, 2014 at 17:40
I am confused about how to flip each digit. If 2 becomes 5, then 6 should become backwards 9, not 9. But if 6 becomes 9, then the flip is just a rotation, so 2 becomes another 2, not 5. — kernigh, Commented Jun 17, 2014 at 18:41
6, 9 rotated 180 deg, 2, 5 flipped horizontally, and 1, 3 in fact are reflections of themselves across the vertical axis. — jimmy23013, Commented Jun 17, 2014 at 19:24
The translations defined in the question are not consistent at all. Why do 2 and 5 flip, but 3 doesn't? — Rynant, Commented Jun 17, 2014 at 19:29
I noticed a curious fact about the switchable numbers: they form opposite binary patterns, i.e. 2=010, 5=101. 6=0110, 9=1001. Can anyone use this fact in their solution? — Jack Aidley, Commented Jun 18, 2014 at 12:01

Destructible Lemon · Accepted Answer · 2016-09-25 03:49:15Z

Turtlèd, 40 bytes (noncompeting)

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

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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

Community · Accepted Answer · 2017-04-13 12:39:01Z

1

PHP, 48 39 bytes

Thanks to Jörg Hülsermann

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

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Older versions

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

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edited Apr 13, 2017 at 12:39

CommunityBot

1

answered Mar 31, 2017 at 14:54

ʰᵈˑ

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\$\begingroup\$ Hey, thanks! Even better, should I post? \$\endgroup\$
– ʰᵈˑ
Commented Mar 31, 2017 at 14:58

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lyxal · Accepted Answer · 2021-03-23 11:36:08Z

1

Vyxal, 16 bytes

kd`0u5uu29u86`⇿ₑ

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Simply push the digits 0 to 9, push the string 0u5uu29u86 (the mapping of each number - u pushes -1 in Vyxal), transliterate and evaluate as Vyxal.

answered Mar 23, 2021 at 11:36

lyxal

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Axuary · Accepted Answer · 2021-03-23 13:05:22Z

1

Excel, 31 bytes

=MID(1060039097,A1+1,1)-(A1<>6)

answered Mar 23, 2021 at 13:05

Axuary

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emanresu A · Accepted Answer · 2022-09-04 06:38:51Z

1

Jelly, 14 bytes

ị“-5--29-860”V

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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.

edited Sep 4, 2022 at 6:38

emanresu A

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answered Mar 31, 2017 at 6:27

Erik the Outgolfer

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\$\begingroup\$ ịV = žh‡ in 05AB1E \$\endgroup\$
– Magic Octopus Urn
Commented Mar 31, 2017 at 17:58

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dave20 · Accepted Answer · 2023-07-07 06:12:44Z

1

Python 3.11 - 24

lambda x:"0.5..29.86"[x]

Based on this Python 2.x answer by Willem.

answered Jul 7, 2023 at 6:12

dave20

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south · Accepted Answer · 2023-07-07 07:15:32Z

1

J, 18 bytes

_1".{&'0x5xx29x86'

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_1".{&'0x5xx29x86'
    {&'0x5xx29x86'  NB. index into a string literal
_1".                NB. eval the result using _1 as a default value

answered Jul 7, 2023 at 7:15

south

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James Williams · Accepted Answer · 2014-06-17 17:32:40Z

0

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

answered Jun 17, 2014 at 17:32

James Williams

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\$\begingroup\$ def f(x): will make it a byte shorter. Also "[a,b][x==5]" is shorter then and equivalent to "a if x==5 else b" \$\endgroup\$
– Pinna_be
Commented Jun 17, 2014 at 21:42
\$\begingroup\$ Also, a small change would be to put the if x==9 last and say x>8 instead, saving a character. \$\endgroup\$
– Pinna_be
Commented Jun 17, 2014 at 21:49
1

\$\begingroup\$ @Pinna_be: You’re forgetting the return. \$\endgroup\$
– Ry-
Commented Jun 18, 2014 at 5:09

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Danstahr · Accepted Answer · 2014-06-17 17:38:53Z

0

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]

answered Jun 17, 2014 at 17:38

Danstahr

1011 bronze badge

\$\begingroup\$ why not altogether f=(lambda x:[-1,-1,5,-1,-1,2,9,-1,8,6][x])(x) \$\endgroup\$
– Dylan Madisetti
Commented Jun 17, 2014 at 18:24
1

\$\begingroup\$ 43 def f(x):print[-1,-1,5,-1,-1,2,9,-1,8,6][x] \$\endgroup\$
– Dylan Madisetti
Commented Jun 17, 2014 at 18:56

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

PowerShell 32

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

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jun 17, 2014 at 20:10

DarkAjax

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Jwosty · Accepted Answer · 2014-06-17 22:38:46Z

0

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

edited Jun 17, 2014 at 22:38

answered Jun 17, 2014 at 22:12

Jwosty

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\$\begingroup\$ Fails for 0 and 8 \$\endgroup\$
– Dancrumb
Commented Jun 17, 2014 at 22:30
\$\begingroup\$ I missed that in the rules, thanks! \$\endgroup\$
– Jwosty
Commented Jun 17, 2014 at 22:31

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Ypnypn · Accepted Answer · 2014-06-17 23:47:22Z

0

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;}

edited Jun 17, 2014 at 23:47

answered Jun 17, 2014 at 17:42

Ypnypn

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\$\begingroup\$ i>8:-1 will return -1 for input 9 when it should return 6, won't it? \$\endgroup\$
– corsiKa
Commented Jun 17, 2014 at 21:52
\$\begingroup\$ @corsiKa Indeed. \$\endgroup\$
– Ypnypn
Commented Jun 17, 2014 at 23:47

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Ypnypn · Accepted Answer · 2014-06-18 01:27:12Z

0

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

edited Jun 18, 2014 at 1:27

answered Jun 18, 2014 at 1:16

Ypnypn

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\$\begingroup\$ 30 bytes: {1,0,6,0,0,3,10,0,9,7}-1:Ans(X+1 \$\endgroup\$
– lirtosiast
Commented Jun 8, 2015 at 1:50

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bacchusbeale · Accepted Answer · 2014-06-18 08:44:16Z

0

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;}

answered Jun 18, 2014 at 8:44

bacchusbeale

1,2636 silver badges7 bronze badges

\$\begingroup\$ Doesn't C++ inherit the abuse of integers for Booleans of C? \$\endgroup\$
– Peter Taylor
Commented Jun 18, 2014 at 9:58
\$\begingroup\$ @PeterTaylor Yes C++ accepts integers, but I don't want 'a' modified until the end. \$\endgroup\$
– bacchusbeale
Commented Jun 18, 2014 at 11:10
1

\$\begingroup\$ No need to modify a. I was thinking that (a==X)?Y:Z can be (a-X)?Z:Y to save a few bytes. \$\endgroup\$
– Peter Taylor
Commented Jun 18, 2014 at 14:13
\$\begingroup\$ Which compiler are you using? I can't find a gcc version that accepts that without #include <iostream> and std::. \$\endgroup\$
– Christoph
Commented Mar 31, 2017 at 7:24

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

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

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jun 19, 2014 at 4:59

rici

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YawarRaza7349 · Accepted Answer · 2014-06-20 04:07:29Z

0

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 (:[])).

answered Jun 20, 2014 at 4:07

YawarRaza7349

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

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 :).

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jun 19, 2014 at 15:02

idiot.py

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\$\begingroup\$ This could be written print[0,-1,5,-1,-1,-1,9,-1,8,6][input()] in Python 2. Also one could increase all the numbers by 1 to save one character. \$\endgroup\$
– seequ
Commented Jun 19, 2014 at 16:58

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Οurous · Accepted Answer · 2014-06-23 23:22:37Z

0

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.

answered Jun 23, 2014 at 23:22

Οurous

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

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)))

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jun 25, 2014 at 19:55

Sylwester

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Martin Ender · Accepted Answer · 2014-09-09 09:21:19Z

0

Ruby, 30 bytes

What, no Ruby solution yet?

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

Takes the input as a command-line argument.

answered Sep 9, 2014 at 9:21

Martin Ender

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kirbyfan64sos · Accepted Answer · 2015-06-09 00:14:03Z

0

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.

edited Jun 9, 2015 at 0:14

answered Jun 8, 2015 at 23:52

kirbyfan64sos

9,1881 gold badge26 silver badges46 bronze badges

\$\begingroup\$ @ThomasKwa Fixed. \$\endgroup\$
– kirbyfan64sos
Commented Jun 9, 2015 at 0:14

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MCMastery · Accepted Answer · 2016-09-23 18:12:22Z

0

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

answered Sep 23, 2016 at 18:12

MCMastery

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ceilingcat · Accepted Answer · 2020-06-11 03:07:35Z

0

C (gcc), 46 27 bytes

f(i){i="BAGAADKAJH"[i]-66;}

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edited Jun 11, 2020 at 3:07

answered Sep 24, 2016 at 0:38

ceilingcat

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The Thonnu · Accepted Answer · 2023-07-05 18:58:51Z

Thunno 2, 14 bytes

6 8u9yuu5u0K$i

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¿£Ṣƥ*ðdiṅ×Ɗ€¿i

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Explanation

6 8u9yuu5u0K$i  # Implicit input
6 8u9yuu5u0     # Push 6,8,-1,9,2,-1,-1,5,-1,0
           K    # Wrap the stack (reversed)
            $i  # Index the input in
                # Implicit output

¿£Ṣƥ*ðdiṅ×Ɗ€¿i  # Implicit input
¿£Ṣƥ*ðdiṅ×Ɗ€¿   # Push compressed list
                # [0,-1,5,-1,-1,2,9,-1,8,6]
             i  # Index the input in
                # Implicit output

l4m2 · Accepted Answer · 2023-07-07 07:18:08Z

0

JavaScript (Node.js), 25 bytes

x=>'0x'+'106003a097'[x]-1

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answered Jul 7, 2023 at 7:18

l4m2

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Stack Exchange Network

Return the flipped version of a number

55 Answers 55

Turtlèd, 40 bytes (noncompeting)

PHP, 48 39 bytes

Vyxal, 16 bytes

Excel, 31 bytes

Jelly, 14 bytes

Python 3.11 - 24

J, 18 bytes

Python - 92

Python - 73 bytes

PowerShell 32

F# - 37 bytes

Java, 75

TI-BASIC, 35

C++ 85

Bash 26

Haskell (full program), 63

Python3: 47

Batch - 79

Zozotez LISP 87

Ruby, 30 bytes

Pyth - 16 bytes

dimwit 24 23 bytes (non-competing)

Explanation:

Try it Here

C (gcc), 46 27 bytes

Thunno 2, 14 bytes

Explanation

JavaScript (Node.js), 25 bytes

Your Answer

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code-golf
number
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55 Answers 55

Turtlèd, 40 bytes (noncompeting)

PHP, 48 39 bytes

Vyxal, 16 bytes

Excel, 31 bytes

Jelly, 14 bytes

Python 3.11 - 24

J, 18 bytes

Python - 92

Python - 73 bytes

PowerShell 32

F# - 37 bytes

Java, 75

TI-BASIC, 35

C++ 85

Bash 26

Haskell (full program), 63

Python3: 47

Batch - 79

Zozotez LISP 87

Ruby, 30 bytes

Pyth - 16 bytes

dimwit 24 23 bytes (non-competing)

Explanation:

C (gcc), 46 27 bytes

Thunno 2, 14 bytes

Explanation

JavaScript (Node.js), 25 bytes

Your Answer

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