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Re: Array Filter and Lookahead

by thundergnat (Deacon)
on Nov 20, 2012 at 17:25 UTC ( #1004760=note: print w/replies, xml ) Need Help??


in reply to Array Filter and Lookahead

Update: added intermediate variables.

my @test = ( "text text text 1 text", "1 text text text 2 text 3 ", "text 1 text text 2 text", "text text text 1 text 2 3.0", "1 2 3 4 5 6 7 8 9 10 11", "text text text text" ); my @filtered = map {/(\d+)(?:\.0*)?\D*$/; $1} @test; print join "\n", @filtered;
yields:
1
3
2
3
11

Or possibly, depending on your needs, something like:

my @filtered = map {/(\d+(?:\.\d*)?)\D*$/; 0 + $1 || ''} @test; print join "\n", @filtered;

Replies are listed 'Best First'.
Re^2: Array Filter and Lookahead
by AnomalousMonk (Chancellor) on Nov 20, 2012 at 19:51 UTC

    The solutions you propose have various problems:

    • handling a number like 3.0, of which daugh016 seems to want to capture only the integer portion;
    • handling 0;
    • and the problem of having capture variables undefined if a match fails (or else having the value of these variables persist from a previous match).

    Here is a possible solution avoiding those problems:

    >perl -wMstrict -le "my @test = ( 'text text text 1 text', '1 text text text 2 text 3 ', 'text 1 text text 2 text', 'text text text 1 text 2 3.0', '1 2 3 4 5 6 7 8 9 10 11', 'text 0', 'text 3.1', 'text text text text', ); ;; 'Zonk' =~ m{ (\w+) }xms; ;; my @filtered = map {/(\d+)(?:\.0*)?\D*$/; $1} @test; printf qq{'$_' } for @filtered; print qq{\n}; ;; @filtered = map {/(\d+(?:\.\d*)?)\D*$/; 0 + $1 || ''} @test; printf qq{'$_' } for @filtered; print qq{\n}; ;; @filtered = map { m{ (\d+) (?: [.] \d*)? \D* \z }xms ? $1 : '' } @test ; printf qq{'$_' } for @filtered; print qq{\n}; " '1' '3' '2' '3' '11' '0' '1' 'Zonk' Argument "Zonk" isn't numeric in addition (+) at -e line 1. '1' '3' '2' '3' '11' '' '3.1' '' '1' '3' '2' '3' '11' '0' '3' ''

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