Regex : Return match elements

ravi45722 has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Regex : Return match elements by choroba (Cardinal) on Jun 24, 2016 at 12:16 UTC
split is your friend. Introducing a capture group in its regex adds the captured separators to the result, but it also adds undefs when the other alternative matches, so you need grep to filter them out. `my @array = grep defined, split / ([\|&]) \|\n/, $str;` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^2: Regex : Return match elements by ravi45722 (Pilgrim) on Jun 24, 2016 at 13:22 UTC
first I also think for split but I am loosing '&' '\|' while spliting. But you did the magic. thanks	[reply]
Re^3: Regex : Return match elements by Marshall (Canon) on Jun 24, 2016 at 14:45 UTC
Split uses a regex (regular expression) to decide when to create elements of the resulting array. The code uses & or \| to decide when to "make a new array element". Normally, in most splits, it is desired to "throw away" the split characters. Classic is: `split /\s+/, $line;` to parse space separated tokens. The use of a capture group in the regex allows the "splitted upon tokens" to appear in the output. This is an unusual situation, but works here.	[reply] [d/l]
Re: Regex : Return match elements by AnomalousMonk (Archbishop) on Jun 24, 2016 at 15:52 UTC
I may be missing something, but this seems to be all about appropriately transforming in-place the `& \|` characters (and any surrounding whitespace). Nothing needs to be extracted. Script: `use warnings; use strict; print qq{running under Perl version: $] \n\n}; my $str = <<EO_STR; must-column08:Submit & must-column10:Delivered must-column08:Submit & must-column10:Delivered One & must-column9:No_e +rror must-column08:See Here & must-column10:Delivered \| must-column9:No_err +or EO_STR print qq{<<$str>>}; print qq{\n\n}; $str =~ s{ \s* ([&\|]) \s* }{\n$1\n}xmsg; print qq{[[$str]]};` [download] Output: `c:\@Work\Perl\monks\ravi45722>perl xform_str_1.pl running under Perl version: 5.008009 <<must-column08:Submit & must-column10:Delivered must-column08:Submit & must-column10:Delivered One & must-column9:No_e +rror must-column08:See Here & must-column10:Delivered \| must-column9:No_err +or >> [[must-column08:Submit & must-column10:Delivered must-column08:Submit & must-column10:Delivered One & must-column9:No_error must-column08:See Here & must-column10:Delivered \| must-column9:No_error ]]` [download] Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^2: Regex : Return match elements by ravi45722 (Pilgrim) on Oct 25, 2016 at 10:15 UTC
I need the output as a array but its returning as A string.	[reply]
Re^3: Regex : Return match elements by AnomalousMonk (Archbishop) on Oct 25, 2016 at 17:07 UTC
I assume from this that you have a solution and need no further advice. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]
Re: Regex : Return match elements by AnomalousMonk (Archbishop) on Jun 24, 2016 at 17:30 UTC
`my @matches = $str =~ /(\w+)-(\w+\|[0-9]+):(\w+\|[0-9]+)\s[&\|\\|](\w+)-(\w+\|[0-9]+):(\w+\|[0-9]+)\s[&\|\\|]/g;` This doesn't address the basic problem set out in your OP, but here are a few notes about the regex quoted therefrom: `(\w+\|[0-9]+)` Because `[0-9]` is a subset of the `\w` character class, and because the `\w` term is first in the ordered alternation, this regex expression is exactly equivalent to `(\w+)` (see Character Classes and other Special Escapes in perlre); `[&\|\\|]` The `\|` alternation metacharacter has no special meaning in a character class, nor do any of the other "standard" metacharacters, so this expression is exactly equivalent to `[&\|]` (there are metacharacters specific to character classes; see Using character classes in perlretut); `[&\|\\|]` This expression appears twice in the quoted regex. Whenever I see repetition, I think refactor. This could be defined once as `my $sep = qr{ [&\|] }xms;` and interpolated as needed, and if it ever needs to change, you only need to worry about changing it in one place (DRY); Take a little whitespace for thy eyes' sake: get to know and love the `/x` modifier (see regex modifiers in perlre). All this allows you to rewrite the original `my @matches = $str =~ /(\w+)-(\w+\|[0-9]+):(\w+\|[0-9]+)\s[&\|\\|](\w+)-(\w+\|[0-9]+):(\w+\|[0-9]+)\s[&\|\\|]/g;` statement as the considerably less eye-bezoggling (IMHO) `my $sep = qr{ [&\|] }xms;` `my @matches = $str =~ /(\w+) - (\w+) : (\w+) \s $sep (\w+) - (\w+) : (\w+) \s $sep/xg;` Again, this doesn't actually fix the original problem, but at least it becomes easier to see the problem (again, IMHO). Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]