[Pdx-pm] prefixing, padding, and joining with commas

[Eric Wilhelm]

# from Joshua Keroes
# on Thursday 12 January 2012 17:06:

>   1. I suspect that $c++ line does nothing.
>   2. sprintf or printf will handle that 0-prefixing with less code.

Using sprintf(), map(), and join() eliminates the four instances of 
duplicate/pseudo-duplicate "$prefix . $something" code and reduces it 
to:

  join(', ', map {$prefix . sprintf("%02d", $_)} $start..$last)

Note the concatenation of commas onto $samples, plus the trailing case 
with special handling for "add last sample w/o a comma".  Using join() 
eliminates this special case at the end.

It is also more efficient (for large strings, repeated concatenation can 
be very expensive vs growing a list.)

Or, if you would rather read your code from left to right:

  use List::oo qw(L);
  L($start..$last)->map(sub{$prefix . sprintf("%02d", $_)})->join(', ');

--Eric
-- 
Issues of control, repair, improvement, cost, or just plain
understandability all come down strongly in favor of open source
solutions to complex problems of any sort.
--Robert G. Brown
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