convert tabs to spaces

Question

Write the shortest possible code which converts tabs to spaces in the input. Tab size should be supplied as a parameter or be hardcoded in the code in a single place.

Spaces on output should point to the right column, e.g. (\t represents a tab character):

a\tb
aa\tb
aaa\tb
aaaa\tb

should become (for tab size 4):

a   b
aa  b
aaa b
aaaa    b

Of course there can be more than one tab in a line.

Line separator and tab character should match the system defaults (e.g. ASCII 10 and 9 on Unix).

Answer 1

Perl 5, 36 bytes

1while s/	/$"x($^I-length($`)%$^I)/e

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Tab length is controlled with -i command-line parameter.

Answer 2

Python 2, 106 bytes

def f(s,w):
 for l in s.split('\n'):
  L=''
  for x in l.split('\t'):L+=' '*(w-(len(L)%w))+x
  print L[w:]

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Answer 3

Vim, 16 bytes

:se ts=4 et
:ret

Answer 4

Pyth, 24 bytes

VQ=+k:NJ"   "d=.[kd|nNJ4)k

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Explanation

VQ=+k:NJ"   "d=.[kd|nNJ4)k
VQ                      )    For each character in the input...
  =+k:NJ"   "d               ... add the character with tab replaced by space
                             to k (initially empty)...
              =.[kd          ... then pad k with spaces...
                   |nNJ4     ... to the nearest multiple of 4 if the character
                             is a tab and 1 otherwise.
                         k   Output k.

Alternatively, if we want to input the tab length, we can do so with Vz=+k:NJ" "d=.[kd|nNJQ)k.
Try it here.

Answer 5

Java 11, 134 bytes

n->s->{for(var l:s.split("\n")){var t="";for(var p:l.split("\t"))t+=" ".repeat(n-t.length()%n)+p;System.out.println(t.substring(n));}}

This time an answer for which I correctly read the challenge.. >.>

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NOTE: Because Java 11 isn't on TIO yet, the String.repeat(int) has been emulated with repeat(String,int) for the same byte-count.

Explanation:

n->s->{                      // Method with int & String parameters and String return-type
  for(var l:s.split("\n")){  //  Split the input by newlines, and loop over the lines:
    var t="";                //   Temp-String, starting empty
    for(var p:l.split("\t")) //   Split the line by tabs, and loop over the parts
      t+=" ".repeat(n-t.length()%n)
                             //    Append `n - length_of_t modulo-n` amount of spaces,
         +p;                 //    as well as part `p` to the temp-String
      System.out.println(    //    Print with trailing new-line:
        t                    //     The temp-String `t`
         .substring(n));}}   //      after we've removed the trailing spaces

Answer 6

Excel VBA, 118

An anonymous VBE immediate window function that takes an input string from range [A1] and an input tab length from range [B1], and outputs to the console.

For Each l In Split([A1],vbLf):Do:i=InStr(1,l,"\t"):l=Replace(l,"\t",Space([B1]-(i-1)Mod[B1]),,1):Loop While i:?l:Next

Ungolfed

Public Sub tabReplace(ByRef value As String, Optional tabLen As Integer = 4)
    Dim line, index As Integer
    For Each line In Split(value, vbLf)
        Do
            Let index = InStr(1, line, "\t")
            Let line = Replace(line, "\t", Space(tabLen - (index - 1) Mod tabLen), , 1)
        Loop While index
        Debug.Print line
    Next
End Sub

Answer 7

Python 2, 103 bytes

def F(I,c):
 while'\t'in I:t=I.find('\t');I=I.replace('\t',' '*(c-(t+~I[:t].rfind('\n'))%c),1)
 print I

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I wanted to evade split and use some replace (tbh I've started with regex).

I replace each \t with c-(t+~I[:t].rfind('\n'))%c number of spaces. Where t - index of current \t and t+~I[:t].rfind('\n') is distance to the closest \n (or start of string) on left.

Answer 8

Wolfram Language (Mathematica), 40 bytes

StringReplace[#,"	"->Array[" "&,4]<>""]&

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Sadly, Mathematica doesn't let you multiply a string by a number to duplicate it, otherwise it would be shorter than Perl.

---

Explanation:

StringReplace[#, Replace all instances of

" " a tab character

->Array[" " with an array of spaces

,4] four long

<>""]& joined to the empty string.