in reply to Capturing substrings with complex delimiter, up to a maximum

Combine split with limit and lookahead-assertion! 

  DB<107> $str=join ",",@captures 
 => "http://abc.org,http://de,f.org,https://ghi.org"

  DB<108> split /,(?=https?:)/,$str,1
 => "http://abc.org,http://de,f.org,https://ghi.org"

  DB<109> split /,(?=https?:)/,$str,2
 => ("http://abc.org", "http://de,f.org,https://ghi.org")

  DB<110> split /,(?=https?:)/,$str,3
 => ("http://abc.org", "http://de,f.org", "https://ghi.org")

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you just need to get rid of the unsplitted rest (if any) 

  DB<122> $n=1
 => 1

  DB<123> @array[0..$n-1] = split /,(?=https?:)/ , $str , $n+1
 => "http://abc.org"

  DB<124> $n=2
 => 2

  DB<125> @array[0..$n-1] = split /,(?=https?:)/ , $str , $n+1
 => ("http://abc.org", "http://de,f.org")

[download]

Cheers Rolf

( addicted to the Perl Programming Language)

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Re^2: Capturing substrings with complex delimiter, up to a maximum
by jkeenan1 (Deacon) on Oct 30, 2013 at 01:33 UTC

    Thank you very much for your rapid response. As was the case with BrowserUK's response, I tried to adapt your suggestion to a subroutine I could easily drop into my test program. 

    sub _rolf_recognize_limited_urls {
  my ($input, $max) = @_;
  my @captures = ();
  @captures[0..$max-1] = split /,(?=https?:)/, $input, $max+1;
  return [ @captures ]; 
}

    [download]

    As was the case with BrowserUK's formulation, the first two of four tests failed. I only got all four tests to past when I grepped for definedness: 

    sub _rolf_recognize_limited_urls {
  my ($input, $max) = @_;
  my @captures = ();
  @captures[0..$max-1] = split /,(?=https?:)/, $input, $max+1;
  return [ grep { defined($_) } @captures ];
}

    [download]

    Thank you very much.

    Jim Keenan

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