# Sort digits by their first occurrence in pi

Given a non-negative number n, sort the digits of n by their first occurrence in pi.

Input can be taken via function cli argument, or STDIN and as a string, char[] or integer. You may output via return value, exit status or STDOUT.

• Related Apr 29, 2017 at 16:38
• Can we take input and output as strings, or as arrays of digits? Apr 29, 2017 at 16:39
• @ETHproductions Clarified. Apr 29, 2017 at 16:40
• A few test cases would be nice. Apr 29, 2017 at 18:15
• Now that 12 answers are already present, all of which performing the same thing, if you are still unclear what is being asked, then it is not the problem of the question. Apr 30, 2017 at 2:30

# Python 3, 40 39 bytes

1 byte thanks to Jonathan Allan.

lambda s:sorted(s,key="145926870".find)


Try it online!

• You can drop the 3, since find will return -1 when an item is not found. Apr 29, 2017 at 17:51

# 05AB1E, 109 7 bytes

Saved 1 byte thanks to Leaky Nun noting that filtering out duplicates is unnecessary.
Saved 2 bytes thanks to Adnan.

žqRvy†J


Try it online!

Explanation

žq       # push pi to 15 decimals (contains all digits but 0)
R      # reverse
vy    # for each char in pi
†J  # move it's occurrences in the input to the front

• 13žsRvy†J for 9 bytes Apr 29, 2017 at 16:29
• @LeakyNun: Oh yeah, duplicates doesn't matter. Thanks :) Apr 29, 2017 at 16:31
• Can you use žq instead of 13žs? Apr 29, 2017 at 17:56
• @Adnan It doesn't seem to work. Apr 29, 2017 at 18:01
• @Adnan: Yes of course. I didn't realize there was another pi constant :) Apr 29, 2017 at 18:05

# Pyth, 8 6 bytes

ox+.n0


Try it here.

-1 thanks to Leaky Nun: The input will provide the 0 if it's ever needed.
Trivial -1 thanks to Jakube: Backtick not needed (ah, how did I miss that, HOW?!?).

• Woohoo, this even beats 05AB1E! Edit: it doesn't beat 05AB1E, and I don't wanna steal :( Apr 29, 2017 at 18:00
• I found it. You don't need the 0 at the end. If the input has a 0, the 0 would be provided by the input; if the input does not have a 0, it won't matter. Apr 29, 2017 at 18:16
• @LeakyNun and you can even save the backtick: ox+.n0 Apr 29, 2017 at 22:14
• OK, disregard the first comment, thanks to LeakyNun and Jakube, I again beat 05AB1E, I hope for good this time. Apr 30, 2017 at 8:06
• That's a beautiful amount of implicit input. May 13, 2017 at 6:27

# Jelly, 10 bytes

“ṀSṪw’ṾiµÞ


Try it online!

Takes input as a string of digits.

-3 bytes thanks to @ETHproductions

Explanation

“ṀSṪw’ṾiµÞ
µ  - Separate chain into function “ṀSṪw’Ṿi and sort atom Þ.
Þ - Sort the input by
i   - Each digit's index in:
“ṀSṪw’     - the literal 3145926870 ...
Ṿ    - transformed into the list 3,1,4,5,9,2,6,8,7,0

• I think 3145926870 can be represented as a 4-digit base-250 string (meaning it takes up 6 bytes instead of 10), but I'm not sure how to compress it as such. Apr 29, 2017 at 16:46
• Does Jelly not have a builtin for pi? Apr 29, 2017 at 16:46
• @mathjunkie but Jelly is not very efficient on string manipulation Apr 29, 2017 at 16:47
• @mathjunkie Yes, but the manipulations to the list take too many bytes Apr 29, 2017 at 16:47
• “ṀSṪw’ will give you 3145926870. Apr 29, 2017 at 16:49

# Japt, 10 9 bytes

8 bytes of code, +1 for the -P flag.

¬ñ!bMP+U


Try it online! Takes input as a string.

### Explanation

¬ñ!bMP+'0  // Implicit input

¬          // Split the input into chars.
ñ         // Sort each char in the resulting list by
!b       //   its index in
MP+U   //     Math.PI + the input.
-P         // Join the result back into a single string.
// Implicit: output result of last expression


## JavaScript (ES6), 54 bytes

f=
s=>[...s].sort((a,b)=>k[a]-k[b],k=9150236874).join
<input oninput=o.textContent=f(this.value)><pre id=o>

Uses strings for I/O.

# Jelly,  8  7 bytes

-1 byte thanks to Dennis (use any existing 0 in the input, clever.)

ØP;ṾiµÞ


Try it online!

### How?

ØP;ṾiµÞ - Main link: string s (char list)
µÞ - sort the characters, c, of s by:
i   -   first index of c in:
ØP      -     pi yield: 3.141592653589793
;     -     concatenate with left: [3.141592653589793, c]
Ṿ    -     un-evaluate: "3.141592653589793,c" (a char list with the digit character c)
if any c is 0 ^ it will then be to the right of all others

• ...and there I was searching for squares - 3820009 (sqrt of 14592468760081) is still 3 digits in base 250. Apr 29, 2017 at 18:25
• The Ṿ in your explanation is misplaced. Apr 30, 2017 at 9:56
• @EriktheOutgolfer - thanks, adjusted. Apr 30, 2017 at 10:38

# CJam, 151210 8 bytes

r{P#c}$ Try it online! -3: Use a string based on the P pi variable instead of a literal. -2: Decided I don't need to uniquify at all, since finding an index takes the first occurrence anyways. -2: Thanks to jimmy23013 for an interesting approach using x mod 65536. Explanation: r{P#c}$ e# Takes an input token
r        e# Take the integer as a string
{P#c}  e# Sorting key:
P      e#  Push P (defaults to 3.141592653589793)
     e#  Convert to string representation
#    e#  Find char's index in the string we made
e#  A '.' will never be found in an integer, but it doesn't matter, since the shifting preserves ideal sorting.
e#  A '0' will be indexed as -1.
c   e#  Convert index to char
e#  This first calculates index % 65536, and then converts to char. We need this because otherwise 0 would be indexed as -1, i.e. smallest index.
e#  We don't need to convert back to integer, since we can use lexicographical sorting.
$e# Sort with key • Yay, beats MATL :) Apr 29, 2017 at 17:53 • tio.run/nexus/cjam#@19UHZCgnFyr8v@/oYGRsYmpmbmFJQA May 1, 2017 at 19:02 • @jimmy23013 Wow that's clever. It's almost like there's a builtin for int(x)%65536, and ci would even convert back to integer. May 2, 2017 at 11:12 # C (clang), 85 73 bytes *z=L"9150236874"-48;s(*a,*b){return z[*a]-z[*b];}f(*t,n){qsort(t,n,4,s);}  Try it online! • @ceilingcat, wow, it took my small mind forever to figure out what you did there!! – jdt Sep 24, 2021 at 16:08 • 69, different IO – l4m2 Sep 26, 2021 at 8:21 • @l4m2 Nice!! I'll update my answer; when I get back to my laptop. -2 bytes – jdt Sep 26, 2021 at 9:08 • @l4m2 65 bytes – jdt Sep 26, 2021 at 9:11 # PHP, 71 Bytes The regex solution is shorter for(;~$c=_3145926870[$i++];)echo str_repeat($c,substr_count($argn,$c));


or

for(;~$c=_3145926870[$i++];)echo str_pad("",substr_count($argn,$c),$c);  Online Versions ## PHP, 78 Bytes for(;~$c=$argn[$i++];)$j[strpos("3145926870",$c)].=$c;ksort($j);echo join($j);  ## PHP, 112 Bytes $a=str_split($argn);usort($a,function($x,$y){return strpos($d="3145926870",$x)<=>strpos($d,$y);});echo join($a);  Online Version • I've added a 69 byte solution. Maybe we can get it down to 66 byte together ;) May 2, 2017 at 14:13 # Ruby, 50 bytes n=gets;"3145926870".each_char{|c|$><<c*n.count(c)}


# C (gcc), 78 bytes

f(char*s){for(char*d="3145926870",*p;*d;d++)for(p=s;*p;)*p++-*d||putchar(*d);}


Try it online!

# MATL, 14 bytes

YP99Y$uj!y=sY"  Try it online! ### Explanation with an example The symbol ; is used as row separator in matrices. So [1 2 3] is a row vector, [1; 2; 3] is a column vector, and [1 2; 3 4] is a square matrix. The latter can also be represented, for clarity, as [1 2; 3 4]  Consider input 2325 as an example. YP % Push approximation of pi as a double (predefined literal) % 3.14159265358979 99Y$   % Variable-precision arithmetic with 99 digits. Gives a string.
% The input 3.14159265358979 is recognized as representing pi
% STACK: '3.141592653589793238462 ··· 707'
u      % Unique entries, keeping order of their first appearance
% STACK: '3.145926870'
j      % Input line as a string
% STACK: '3.145926870', '2352'
!      % Transpose
% STACK: '3.145926870', ['2'; '3';'5'; '2']
y      % Duplicate the second-top element in the stack
% STACK: '3.145926870', ['2'; '3';'5'; '2'], '3.145926870'
=      % Test for equality, with broadcast. This gives a matrix with
% all pairwise comparisons)
% STACK: '3.145926870', [0 0 0 0 0 0 1 0 0 0 0;
%                        1 0 0 0 0 0 0 0 0 0 0;
%                        0 0 0 0 1 0 0 0 0 0 0;
%                        0 0 0 0 0 0 1 0 0 0 0]
s      % Sum of each column
% STACK: '3.145926870', [1 0 0 0 1 0 2 0 0 0 0]
Y"     % Run-length decoding. Implicitly display
% STACK: '3522'


# C# Interactive, 37 36 Bytes

i.OrderBy(c=>"145926870".IndexOf(c))


Actually you have to execute this in the C# interactive for proper results, but I guess this is what you meant with exit status. The variable i actually is the input variable (it can be for example a string), so it's basically the method parameter.

I think the code itself is pretty straight forward.

• Where's the 3?
– Paul
May 1, 2017 at 13:44
• @Paul it's not neccessary, as it returns -1 if the element isn't found. May 1, 2017 at 13:47
• This is just a snippet of code though, I'm pretty sure even in interactive you have to specify why i is somewhere so it can be taken as input. Also if you're saying C# you have to include using System.Linq; into the byte count. However, if this is Interactive you should specify the language as C# Interactive not solely C#. May 18, 2017 at 13:13
• @TheLethalCoder I updated it to C# Interactive. The using isn't neccesaary in the interactive, as it's included automatically. May 18, 2017 at 13:16

# PHP, 66 65 bytes

Saved 1 byte thanks to Titus.

while(~$d=_3145926870[++$i])echo preg_filter("/[^$d]/",'',$argn);


# APL (Dyalog Unicode), 13 bytes

{⍵[⍵⍋⍨14⍕○1]}


Try it online!

○1 Pi times 1.

14⍕ convert to a string with 14 decimal digits. This includes all unique digits except 0.

⍵⍋⍨ the indices that would sort the input string ⍵ according to order given by the previous string.

⍵[...] index with those indices into the input to sort it.

# 05AB1E, 5 6 bytes

Had to realise that 0 is not present in the standard length pi constant.

Σтžsyk


Try it online!

Σтžsyk
Σ      Sort by the result of code
тžs   Push 100 digits of pi
yk  Index of digit in pi

• Too bad you needed that zero for this method. It should be optimal for this language at least. Can't ask for more than that :) May 18, 2017 at 13:24

# Java 7, 110 bytes

String c(String s){String r="";for(char i:"3145926870".toCharArray())r+=s.replaceAll("[^"+i+"]","");return r;}


Explanation:

String c(String s){                       // Method with String parameter and String return-type
String r="";                            //  Result String
for(char i:"3145926870".toCharArray())  //  Loop over the characters of "3145926870"
r+=s.replaceAll("[^"+i+"]","");       //   Append the result-String with all the occurrences of the current character
//  End of loop (implicit / single-line body)
return r;                               //  Return the result-String
}                                         // End of method


Test code:

Try it here.

class M{
static String c(String s){String r="";for(char i:"3145926870".toCharArray())r+=s.replaceAll("[^"+i+"]","");return r;}

public static void main(String[] a){
System.out.println(c("12345678908395817288391"));
}
}


Output:

33311145599922688888770


## Clojure, 38 bytes

#(sort-by(zipmap"3145926870"(range))%)


Input in string, returns a sequence of characters. zipmap creates a "dictionary" object, which can be used in a function context as well.

(f "1234")
(\3 \1 \4 \2)


If input digits were guaranteed to be unique then you could simply do #(filter(set %)"3145926870").

# PHP, 69 68

for(;(~$d=$argn[$j++])||~$c=_3145926870[$i+++$j=0];)$c==$d&&print$d;  Still beaten by preg_filter but I thought it was quite nice itself. Maybe someone can golf off some bytes. • $c!=$d?:print$d as alternative for $c==$d&&print$d I only see in the moment May 2, 2017 at 14:21 • _3145926870 instead of "3145926870" save 1 Byte May 2, 2017 at 14:26 • for(;(~$d=$argn[$j++])?:~$c=_3145926870[++$i+$j=0];$c!=$d?:print$d); is also a working alternative May 2, 2017 at 14:57

# Husk, 4 bytes

Ö€İπ


Try it online!

Input as a list of digits.

# Pip, 10 bytes

PI.0@?_SKa


Try it online!

### Explanation

       SKa  Sort the command-line argument a by this key function:
@?_      Index of first occurrence in
PI.0         Pi (3.141592653589793) concatenated with 0


If the 0 isn't added, PI@?0 returns nil, which behaves... strangely... when used as a sorting key.

# Vyxal, 8 bytes

µ»×₍+=»ḟ


Try it Online!

µ Sort by

ḟ first index in

»×₍+=» compressed integer 145926870

• Try it Online! for 6 bytes Jun 18 at 0:43

# Perl 6, 34 bytes

*.comb.sort:{3145926870.index: $_}  Try it *\ # WhateverCode lambda (this is the parameter) .comb # split into digits .sort: { # sort by 3145926870.index:$_ # its index in this number
}

• you can save 1 byte by dropping '3' from the lookup.
– jdt
Aug 13, 2021 at 23:34

# k, 19 bytes

{x@<"3145926870"?x}


Explanation:

{                 } /function(x)
"3145926870"?x  /for each x: "3145926870".index(x)
<                /get indices with which to sort
x@                 /sort x by those indices


# Japt, 6 bytes

Input as a string, output as an array of digit strings

¬nUiMP


Try it

# TI-Basic, 100 bytes

Input Str1
seq(expr(sub(Str1,I,1)),I,1,length(Str1→A
seq(1+sum(not(cumSum(Ans(I)={3,1,4,5,9,2,6,8,7}))),I,1,dim(Ans→B
SortD(ʟB,ʟA
sum(seq(₁₀^(I-1)ʟA(I),I,1,dim(ʟA


Takes input as a string. Outputs a number that is stored in Ans` and is displayed at the end.