regex help

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

Hiya monks, I have to read through csv files and looking for one particular line. Then I have to grep all the numbers behind it. Here is a snippet...

$string = 'Total requests:,20,30,40,50,60' #the list could go on

if ($string =~ m/Total requests:,*?(\d+),(\d+),(\d+),(\d+)/)
#don't know how to do this if to grep all the numbers in that line
[download]

The thing is I have no clue how to match all the instances of (\d+) -- maybe with '(,\d+)+'? And I would like to push all the matched numbers into an array using $1, $2, $3.... in order, if that is possible... Any help is appreciated

Comment on regex help Download Code

Replies are listed 'Best First'.
Re: regex help by kennethk (Abbot) on Nov 12, 2009 at 20:59 UTC
Is there a particular reason this need to be done all at once? Assuming you have a good reason for not using one of the many CSV-parsing modules (e.g. Text::CSV), it would be a lot clearer to do something like: `if ($string =~ m/Total requests:/) { @array = split /,/, $string; }` [download] rather than trying to do a match and capture at the same time. If you have your heart on capturing things in a regular expression, you could do `if ($string =~ m/Total requests:/) { @array = $string =~ /(\d+)/g; }` [download] But I'm willing to bet that your life would be easier with just a CSV-parsing module. Incidentally, your suggestion of `(\d)+` will not work because you will repeatedly overwrite your result and hence will only get the last match (60 in your example).	[reply] [d/l] [select]
Re: regex help by JadeNB (Chaplain) on Nov 12, 2009 at 23:29 UTC
As kennethk and ikegami point out, the crucial thing to realise is this snippet from Matching in list context: If the `/g` option is not used, `m//` in list context returns a list consisting of the subexpressions matched by the parentheses in the pattern, i.e., (`$1` , `$2` , `$3` ...). (Note that here `$1` etc. are also set, and that this differs from Perl 4's behavior.) When there are no parentheses in the pattern, the return value is the list `(1)` for success. With or without parentheses, an empty list is returned upon failure. That's the motivation for the seemingly strange `@array = $string =~ m/$regex/` pattern (which parses as `@array = ($string =~ m/$regex/)`) in kennethk's post.	[reply] [d/l] [select]
Re: regex help by ikegami (Patriarch) on Nov 12, 2009 at 21:06 UTC
`if (my @totals = $string =~ m/Total requests:,*?(\d+),(\d+),(\d+),(\d+ +)/)` [download]	[reply] [d/l]
Re: regex help by oha (Friar) on Nov 13, 2009 at 15:01 UTC
`my @out = /,(\d+)/g;` [download] works for the case you said, or if you require to match against "Total request": `my @out = grep { defined } /(?:Total requests:\|,(\d+))/g;` [download]	[reply] [d/l] [select]