Re: Array Filter and Lookahead

[thundergnat]

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;

[AnomalousMonk]

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' ''