Talk:Align columns

J solution

I haven't read the J solution in depth yet, but it appears more complex than may be necessary. For example, with 'LEFT CENTER RIGHT'=:i.2 we can solve the task thus:

  (#~ 0 1 $~ #) (9!:17 CENTER #~ 2 [ 9!:7 ' '$~11) (]":) 4 :'<;._2&.(,&x)y'S:0 /'$';LF;text
  Given        a         text     file    of     many      lines,    where   fields within   a    line 
   are     delineated     by       a    single 'dollar'  character,  write     a                       
   that      aligns      each    column   of    fields       by     ensuring  that  words    in   each 
  column      are     separated    by     at     least      one                                        
 Further,    allow       for      each   word     in         a       column    to     be   either left 
justified,   right    justified,   or   center justified   within     its                              

Replacing CENTER with LEFT or RIGHT to taste.

Now, of course, the justification selected applies to every word. If we want to be able to treat each word (or column) independently, there are other methods. Even for this more general specification, I'm still not convinced that the large explicit verb is required, but I'll have to review it in detail to confirm.

I concur that your solution is adequate to the specified task. It should replace the one I posted. I wrote mine without knowing about 9!:y. Thank you for this more skillful solution, Dan. --TBH 22:58, 1 December 2008 (UTC)

I've just noticed that the code proposed above does not compensate for the inconsistent input data, which lacks the delimiter at the end of some lines. (It does not seem right to me to have the example text have such an irregularity when nothing about the task suggests that data-quality testing is relevant, but, that's what we've been given.) --TBH 00:28, 2 December 2008 (UTC)

Output Question

Given that the lines contain varying numbers of fields, when a justified line is output should the program
A) only output the justified fields that the line contains, or
B) output spaces for the columns when the line does not contain all the columns?

Hi, assume that the output should look good visually, and that lines will never be wrapped when displayed so trailing whitespace is irrelevant. --Paddy3118 03:39, 2 December 2008 (UTC)