Through the bases

Question

Through the bases

In this challenge, you will be taking a number through all the bases of the rainbow

Given an input, n, you will output n in every base from 9 to 2, and back up to 9. That's 9 8 7 6 5 4 3 2 3 4 5 6 7 8 9.

Example:

>>> 16
17
20
22
24
31
100
121
10000
121
100
31
24
22
20
17

Rules:

• You input can be a string or a number.
• Your output may be separated by new lines, spaces, commas, or tabs.
• You may use built in functions.
• Shortest code wins!

Answer 1

CJam, 14 bytes

riF,f{7-z2+bN}

Try it online in the CJam interpreter.

How it works

ri             e# Read an integer I from STDIN.
  F,           e# Push [0 ... 14].
    f{       } e# For each B in that range, push I and B; then:
      7-z2+    e#   Compute abs(B - 7) + 2.
               e#   This maps [0 ... 14] to [9 ... 2 ... 9].
           b   e#   Perform base conversion.
            N  e#   Push a linefeed.

Answer 2

Pyth, 14 bytes

V+_Jr2TtJjkjQN

Needs more work, most code is spent generating 9..2..9.

Answer 3

Pyth, 18 15 14 bytes

Saved 3 bytes thanks to Dennis and 1 thanks to Jakube!

V+r9 1r3TjkjQN

Explanation:

V                     For N in
 +r9 1r3T             the list [9,8,...3,2,3,...,8,9],
           jQN        convert the input to base N (returns a list),
         jk           join the list into a string, implicitly printed.

Try it online.

Answer 4

Haskell, 59

0%_=0
k%b=div k b%b*10+mod k b
g n=map(n%)$[9,8..3]++[2..9]

First, recursively defines a binary operator % to do base conversion, representing the output as a decimal number rather than a string. The function g converts the input n to each base from 9 to 2 and back up.

There's probably a shorter approach, advice is welcome. Saved 2 chars on parens thanks to nimi.

Answer 5

Julia, 43 bytes

n->for i=[9:-1:2,3:9] println(base(i,n))end

This creates an unnamed function that accepts and integer and prints to STDOUT on separate lines. The base function takes two integers: a base (i) and a number (n) and returns the string representation of the number in the given base. Here we just loop through the required bases and print.

Answer 6

Bash + dc, 27

echo {{9..2},{3..9}}o$1p|dc

Answer 7

JavaScript (ES6), 57 bytes

f=n=>[...`987654323456789`].map(v=>n.toString(v)).join` `

CoffeeScript, 57 bytes

Different approach:

f=(n)->[-7..7].map((v)->n.toString 2+Math.abs v).join ' '

JavaScript (ES5), 97 bytes

function f(n){return'987654323456789'.split('').map(function(v){return n.toString(v)}).join(' ')}

Demo

function f(n) {
  return '987654323456789'.split('').map(function(v) {
    return n.toString(v)
  }).join(' ')
}

document.body.innerHTML = f(16)

Answer 8

Python 2, 79

g=lambda b,k=input():k and g(b,k/b)*10+k%b
c=7;exec"print g(abs(c)+2);c-=1;"*15

The function g converts a number k to a base b. We can take k as the program input because Python initializes default arguments when the function is defined, not each time it's called. We get the desired sequence of bases by taking the range [-7, -6, ..., 6, 7], taking the absolute value, and adding 2.

Answer 9

JavaScript SpiderMonkey 31 (1.8), 47 bytes

n=>[for(i of`987654323456789`)n.toString(i)]+''

It doesn't get simpler than this.

Answer 10

Pip, 14 = 13 + 1 bytes

Uses the -n flag.

aTB2+AB(-7,8)

GitHub repository for Pip

Takes the number as a command-line argument.

        -7,8   Range containing integers from -7 through 7
     AB(    )  Absolute value of each
   2+          Add 2 to each
aTB            Convert command-line arg to each base
               Print resulting list, newline-separated (-n flag)

It's amazing how all the golfing languages are getting the same score here.

Answer 11

JavaScript (ES5), 69 66 65 bytes

function f(o){for(i=15;i--;)console.log(o.toString(i>7?i-5:9-i))}

Answer 12

Ruby, 44 bytes

a=->n{(0..14).map{|j|p n.to_s((j-7).abs+2)}}

Call the lambda with a.call(number). This prints out with quotes around each line because p is shorter than puts. I'm assuming this is allowed.

Answer 13

APL, 52 bytes

I'll admit, this could use more golfing.

{n←⍵⋄⊃{⍺,' ',⍵}/{⊃,/⍕¨(~∧\0=e)/e←(10⍴⍵)⊤n}¨2+|8-⍨⍳15}

it is limited to at most 10 digits output

suggestions for improvement welcome

output for 16 looks like

17 20 22 24 31 100 121 10000 121 100 31 24 22 20 17