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Re^2: How can I sort my array numerically on part of the string? (updated)

by LanX (Cardinal)
on Dec 02, 2020 at 02:09 UTC ( #11124496=note: print w/replies, xml ) Need Help??


in reply to Re: How can I sort my array numerically on part of the string? (updated)
in thread How can I sort my array numerically on part of the string?

>  sort { ($a=~/(\d+),/)[0] <=> ($b=~/(\d+),/)[0]

You need that (...)[0] for the match to return the captures in list context, ( <=> is enforcing scalar context and m// only returns captures in list context otherwise boolean )

I'm wondering if there is a prettier solution for that.

The Schwartzian transform doesn't have that limitation.

... map { [$_, /(\d+),/] } @list;

should do already.

update

clarification: any better solution than (...)[0] to get list context ?

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

Replies are listed 'Best First'.
Re^3: How can I sort my array numerically on part of the string? (updated)
by tybalt89 (Prior) on Dec 02, 2020 at 03:17 UTC

    Here's a capture in list context. Prettier?

    #!/usr/bin/perl use strict; # https://perlmonks.org/?node_id=11124461 use warnings; my @list = ( '1,cat', '2,dog', '22,mouse', '11,eel', '001,elk', '13,mi +nk'); my @n; @n[ /(\d+),/ ] .= "$_\n" for @list; print grep defined, @n;

    This is why perl is fun :)

      > This is why perl is fun :)

      and so memory efficient ...

      > Prettier?

      nope! :)

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery

        TY guys I learned a lot from your suggestions, and no one made me feel "dumb"... LOVE IT..

        Happy Holidays to all may Karma be your friend..

Re^3: How can I sort my array numerically on part of the string? (updated)
by misterperl (Scribe) on Dec 02, 2020 at 13:24 UTC
    TY I didnt realise I needed the [0] I'm gonna try that. Although I'm unclear as to what "list" is involved with $a and $b which appear to be scalar?

      > > You need that (...)[0] for the match to return the captures in list context, ( <=> is enforcing scalar context and m// only returns captures in list context otherwise boolean )

      DB<96> $_= "123,foo" DB<97> p scalar m/(\d+,)/ # boolean value 1 DB<98> p m/(\d+,)/ # list of captures 123, DB<99>

      see https://perldoc.perl.org/perlop#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, that is, ($1, $2, $3...) (Note that here $1 etc. are also set). 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.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery

      the list is the return values of the regex

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