Expand some number

Question

This challenge is based on this Stackoverflow question.

With a positive number as input, output it as the sum of each digit multiplied by its power-of-10 representation.

Input

A number, as an integer, a string or a list of digits/characters.

The number will be strictly positive.
If you accept the number as a string or list, it will not start with a 0.

Output

A string representing a sum of each relevant base-10 digits, each multiplied by its respective base-10 power. A sum is represented as a + b. You may use up to one space around each side of the + sign if you want. The operands are listed in descending order.

0 can never be a valid operand.
The + sign (surrounded or not by spaces) may not be the leading or trailing part.

Examples

Input       Output
12          10 + 2
         or 10+2
         or 10 +2
         or 10+ 2
9           9
123         100 + 20 + 3
10          10
101         100 + 1

Invalid outputs

2           1 + 1
10          10 + 0
1           0 + 1
12          + 10 + 2
12          10 + 2 +
12          2 + 10

This is code-golf so the shortest code in bytes wins!

What is the expected output for input 0? (If 0 is an invalid input in the first place, then it should be removed from the invalid output examples IMO) — Pedro A, Sep 10, 2018 at 11:55

maxb · Accepted Answer · 2018-09-27 13:30:14Z

MathGolf, 12 11 10 bytes

hrzúm*ç'+u

Try it online!

Explanation

The first command is not needed as input can be given as a list of digits.

(▒           Convert to a list of digits)
 h           Get length of input list without popping
  r          Push range(a)
   z         Reverse sort
    ú        Map i -> 10**i for each element in list
     m*      Element-wise multiplication
       ç     Filter faulty items in list
        '+   Push "+"
          u  Join with separator

I might add a pairwise multiplication operator that is one byte, but that's not currently part of the language. Then I could remove one byte from this solution.

tybocopperkettle · Accepted Answer · 2022-11-12 23:11:48Z

2

Vyxal, 8 bytes

ẏṘ↵*ꜝ\+j

Takes input as a list of digits.

Try it online, or verify all test cases.

Explanation:

   *       # Multiply each digit in the input by the corresponding value in:
ẏ          # the range from 0 to the length of the input
 Ṙ         # reversed
  ↵        # with each value mapped to 10^n.
    ꜝ      # Remove falsey values.
     j     # Join on
       \+  # "+"

answered Nov 12, 2022 at 23:11

tybocopperkettle

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

1

Wolfram Language (Mathematica), 58 bytes

StringRiffle[ToString/@(NumberExpand[#]/.(0->Nothing)),"+"]&

In Use:

In[101]:= StringRiffle[ToString /@ (NumberExpand[#] /. (0 -> Nothing)), "+"] &[101]
Out[101]= "100+1"

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Sep 10, 2018 at 1:49

ktm

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Ipor Sircer · Accepted Answer · 2018-09-11 12:53:50Z

1

BASH, 86 83 bytes

Try it online!

for((t=$1;++m<${#1};t=10#$g)){
g=${t#?}
b+=${t/$g}${g//?/0}+;}
a=$b$t
echo ${a//+0}

edited Sep 11, 2018 at 12:53

answered Sep 11, 2018 at 6:20

Ipor Sircer

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DLosc · Accepted Answer · 2018-09-11 16:15:24Z

Pip, 21 bytes

W+:axPB['+POa0Ma];@>x

Takes input as a command-line argument. Try it online!

Explanation

Partially inspired by nimi's Haskell answer.

                       x is empty string; a is 1st cmdline arg (implicit)
W                      While loop
 +:a                    Loop condition: a, after unary + is applied in-place
                         Unary + adds 0 to a number, with the side effect of converting it to
                         standard numerical form; in this case, that means eliminating leading zeros
                        Inside the loop, we know that a is nonzero and has no leading zeros
       [        ]       Construct a list containing the following items:
        '+               A + character
          POa            Pop the first character from a (leaving a one character shorter)
             0Ma         Map 0 to a, giving a list of 0's with the same length as a
                        E.g. if a was 123, the list is ["+" 1 [0 0]] and a becomes 23
    xPB                 Push this list to the back of x
                        Since x is a string, PB will cast the list to a string and append it to x
                        The default list -> string format is to concatenate all the items, so in
                        the above example, x will have "+100" appended
                 ;     Required for parsing
                  @>x  Take all but the first character of x and autoprint it

Here's a less creative map-and-filter approach, also 21 bytes:

_FI_*t**BMZaRV,#aJ:'+

Try it online!

I tried a few ways to golf this, but ran into parsing problems that forced me back up to 21. Quite possibly there's a shorter way to do it.

Josh B. · Accepted Answer · 2018-09-13 05:04:51Z

1

Python 3, 114 bytes

s,n=[],input()
[s.append(("+"+n[-i-1]+"0"*i)*(int(n[-i-1])>0))for i in range(len(n))]
print("".join(s[::-1])[1:])

Try it online!

edited Sep 13, 2018 at 5:04

user45941

answered Sep 13, 2018 at 4:47

Josh B.

1351 silver badge6 bronze badges

\$\begingroup\$ Why do you use a list comprehension to simulate a for loop that fills a list? Anyhow, 66 bytes. \$\endgroup\$
– Jonathan Frech
Sep 14, 2018 at 2:16
\$\begingroup\$ I think I planned on having it be on one line but then I changed my mind and didn't reflect that back into the design; now that you say this, I think I will go back and make this cleaner. \$\endgroup\$
– Josh B.
Sep 14, 2018 at 2:32

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Jo King · Accepted Answer · 2018-09-13 07:54:15Z

brainfuck, 116 bytes

--->-[<+>-----]>,[>,]<[<]>[<<[->+>-<<]>>[[>]>[<<[<]>-----.+++++[>]]<<[<]>[->+<<+>]>.,>[[-<+>]<[<]<.>>[>]>],+<<[<]]>]

Try it online!

Explanation:

--->-[<+>-----]     Push 48
Tape: 48 0'
>,[>,]<[<]          Get all inputted digits
Tape: 48 0' digits
>[                  Loop over each digit
  Tape: 48 0 d' igits
  <<[->+>-<<]       Subtract 48 from the digit       
  Tape: 0' 48 d-48 igits
  >>[               If the digit is not a zero
     [>]>[          Check if the flag is set
        [<]>-----.  Subtract 5 from the 48 to print a plus
        +++++[>]    Restore the 48
     ]
     <[->+<<+>]     Restore the 48 and the first digit
     Tape: 48 0' d igits
     >.,            Print and remove the first digit
     Tape: 48 0 0' igits
     >[             For each of the remaining digits
        [-<+>]      Move it over one
        <[<]<.      Print a zero
        >>[>]>      Move to the next digit
     ]
     Tape: 48 0 digits? 0 0'
     ,+<<[<]        Set the plus flag
     Tape: 48 0' digits? 0 1
  ]
  Tape: 48 0' digits?
>]

Jo. · Accepted Answer · 2018-09-28 06:51:29Z

1

PHP, 89 bytes

<?for($i=0;$i<$l=strlen($a=$argv[1]);$i++)echo$a[$i]?($i?"+":"").$a[$i]*10**($l-$i-1):"";

Try it online!

answered Sep 28, 2018 at 6:51

Jo.

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G B · Accepted Answer · 2018-09-28 10:35:21Z

1

Ruby, 55 bytes

->n{w=-1;(n.digits.map{|x|x*=10**w+=1}-[0]).reverse*?+}

Try it online!

edited Sep 28, 2018 at 10:35

answered Sep 28, 2018 at 10:13

G B

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wooshinyobject · Accepted Answer · 2018-09-28 13:06:08Z

1

MBASIC, 131 bytes

1 INPUT N$:N=VAL(N$):FOR P=LEN(N$)-1 TO 0 STEP -1:T=10^P:X=INT(N/T):G=X*T
2 IF G>0 THEN PRINT G;:N=N-G:IF N>0 THEN PRINT"+";
3 NEXT P

Input a number as a string, allowing us to walk it's length, subtracting power of 10 multiples as we go.

? 12
10 + 2

? 9
9

? 123
100 + 20 + 3

? 10
10

? 101
100 + 1

edited Sep 28, 2018 at 13:06

answered Sep 23, 2018 at 22:12

wooshinyobject

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The Thonnu · Accepted Answer · 2023-08-09 16:17:05Z

1

Thunno 2, 9 bytes

Żre×0o'+j

Try it online!

Note: 0o could also be æ; or Dị.

Explanation

Żre×0o'+j  '# Implicit input
Żr          # Push (length..0]
  e         # Ten power of each
   ×        # Multiply with input
    0o      # Remove zeros
    æ;      # OR truthy items only
    Dị      # OR filter by itself
      '+j  '# Join by "+"
            # Implicit output

answered Aug 9, 2023 at 16:17

The Thonnu

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Jordan · Accepted Answer · 2023-08-09 20:09:54Z

1

Ruby `-pl`, 47 bytes

gsub(/.(?=.)/){$&+?0*$'.size+?+}
gsub /\+0+/,''

Attempt This Online!

edited Aug 9, 2023 at 20:09

answered Aug 9, 2023 at 19:49

Jordan

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Stack Exchange Network

Expand some number

Input

Output

Examples

Invalid outputs

42 Answers 42

MathGolf, 12 11 10 bytes

Explanation

Vyxal, 8 bytes

Wolfram Language (Mathematica), 58 bytes

BASH, 86 83 bytes

Pip, 21 bytes

Explanation

Python 3, 114 bytes

brainfuck, 116 bytes

Explanation:

PHP, 89 bytes

Ruby, 55 bytes

MBASIC, 131 bytes

Thunno 2, 9 bytes

Explanation

Ruby `-pl`, 47 bytes

Your Answer

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Expand some number

Input

Output

Examples

Invalid outputs

42 Answers 42

MathGolf, 12 11 10 bytes

Explanation

Vyxal, 8 bytes

Wolfram Language (Mathematica), 58 bytes

BASH, 86 83 bytes

Pip, 21 bytes

Explanation

Python 3, 114 bytes

brainfuck, 116 bytes

Explanation:

PHP, 89 bytes

Ruby, 55 bytes

MBASIC, 131 bytes

Thunno 2, 9 bytes

Explanation

Ruby -pl, 47 bytes

Your Answer

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Ruby `-pl`, 47 bytes

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