How to slice complicated string into an array

theNeuron has asked for the wisdom of the Perl Monks concerning the following question:

How to slice this string into an array?

"word1",word2,"word3,word4"

result should be [ 'word1', 'word2', 'word3,word4' ]

That is if the word is surrounded by apostroph don't include it into the result.

The regex seems to be simple: (?: "([^"]*)" | ([^,]) )(?:,|$), but to my surprise both the matched and unamtched parenthesis contribute to the result, making it something like

[ 'word1', undef, undef, 'word2', 'word3,word4', undef ]

I have tried to make use of %+ which should use the leftmost defined result. That works ok, but the code seems to be too unreadable for what it does:

while (
  m/
    (?:                # non-capturing braces
      "(?<val>[^"]*)"  # Find either string delimited by '"'
      |                # or
      (?<val>[^,]*)    # string up to next ','
    )
    (?:,|$)            # After which there is either , or end of line
  /gx
) {
  push @input, $+{val};
}
[download]

I have tried to use @input = map { %+{val} } m/.../gx, but that fills the whole array with just the last match from whole string.

Is there a way to avoid the while + push loop and store the results in to array directly, just for the sake of making the code simpler and nicer?

Many thanks

Vlad

Comment on How to slice complicated string into an array Select or Download Code

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Re: How to slice complicated string into an array by Corion (Patriarch) on Feb 26, 2016 at 11:54 UTC
Have you thought about using Text::CSV_XS for parsing your CSV data?	[reply]
Re^2: How to slice complicated string into an array by theNeuron (Novice) on Feb 26, 2016 at 12:16 UTC
No I haven't. And as I just replied above, external module is not very helpful in my environment. Thank you for the tip though.	[reply]
Re^3: How to slice complicated string into an array by Corion (Patriarch) on Feb 26, 2016 at 12:23 UTC
See Yes, even you can use CPAN, and also note that Text::CSV is pure Perl and can be installed as part of your code.	[reply]
Re^4: How to slice complicated string into an array by jdporter (Paladin) on Feb 26, 2016 at 17:23 UTC
Re^5: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 17:32 UTC
Some notes below your chosen depth have not been shown here
Re: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 11:53 UTC
Is that CSV? Then use Text::CSV / Text::CSV_XS. `use warnings; use strict; my $line = q{"word1",word2,"word3,word4"}; use Text::CSV; my $csv = Text::CSV->new({binary=>1,auto_diag=>2}); $csv->parse($line); use Data::Dumper; print Dumper( [ $csv->fields() ] ); __END__ $VAR1 = [ 'word1', 'word2', 'word3,word4' ];` [download]	[reply] [d/l]
Re^2: How to slice complicated string into an array by theNeuron (Novice) on Feb 26, 2016 at 12:15 UTC
Yes, that is csv and I should have mentioned it. That module is not part of distribution (at least to the perl I have) which would limit the script usability in our environment. But thank you for the pointer.	[reply]
Re^3: How to slice complicated string into an array by poj (Abbot) on Feb 26, 2016 at 13:03 UTC
As a core module `Text::ParseWords` is convenient for simple cases. `# perl use strict; use Text::ParseWords; use Data::Dumper; my $str = '"word1",word2,"word3,word4"'; my @words = quotewords(',', 0, $str); print Dumper \@words;` [download] poj	[reply] [d/l] [select]
Re^3: How to slice complicated string into an array by Arunbear (Prior) on Feb 26, 2016 at 12:38 UTC
Can you use cpanminus to install it?	[reply]
Re: How to slice complicated string into an array by AnomalousMonk (Archbishop) on Feb 26, 2016 at 14:31 UTC
I think I like the Text::CSV or Text::ParseWords module-based parsing approaches a bit better, but if you have Perl version 5.10+, you can use a regex approach that's almost identical to your OPed regex if you take advantage of the `(?\|...\|...)` "branch reset" construct (see Extended Patterns in perlre): `c:\@Work\Perl\monks>perl -wMstrict -le "use 5.010; ;; use Data::Dump qw(dd); ;; my $s = '\"word1\",word2,\"word3,word4\"'; ;; my @ra = $s =~ m{ (?\| \"([^^\x22])\" \| ([^,]+) ) (?:,\|$) }xmsg; dd \@ra; " ["word1", "word2", "word3,word4"]` [download] (Note that what appears above as `\"([^^\x22])\"` due to the peculiarities of Windose command line interpretation and the limitations of my personal REPL should really be `"([^\x22])"` or better yet `"([^"])"`) Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re: How to slice complicated string into an array by ww (Archbishop) on Feb 26, 2016 at 12:29 UTC
FWIW and not a part of your problem, but it appears that what you're calling an "apostroph(sic)" is a comma (at least in all the flavors of English I know) and not an apostrophe. Imprecise or incorrect language is confusing; sometimes even to the person using it!	[reply]
Re: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 11:40 UTC
If using match operator in list context, then also prefix with `grep defined,`	[reply] [d/l]
Re^2: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 11:49 UTC
That didn't come to my mind, thank you! `grep { defined }` it is.	[reply] [d/l]
Re: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 13:39 UTC
Hi, there is a nice old core module that could help. `use v5.14; use Text::ParseWords; my $line = q{"word1",word2,"word3,word4"}; my @words = quotewords( ",", 0, $line ); foreach( @words ){ say $_; }` [download]	[reply] [d/l]
Re^2: How to slice complicated string into an array by Anonymous Monk on Feb 26, 2016 at 13:46 UTC
Sorry for that post, I haven't seen poj's answer before.	[reply]
Re: How to slice complicated string into an array by Anonymous Monk on Feb 29, 2016 at 08:40 UTC
Buy the Perl Cookbook which has a neat solution: `my @a; my $s = '"word1",word2,"word3,word4"'; push(@a, $+) while $s =~ m {"([^\"\\](?:\\.[^\"\\])*)",? \| ([^,]+),? \| ,}gx; print "\|$_\|\n" for (@a);` [download]	[reply] [d/l]