Gauthier, Dave wrote:
> Getting unwanted list elements when using split with regex. Here's an
> example....
>
> $str = "abc=In";
> @arr = split(/[a-zA-Z0-9]/,$str);
> foreach $a (@arr)
> {print "$a\n";}
>
> I get...
>
> <>
> <>
> <>
> <=>
>
> If I change "abc=In" to "abcdef=In", I get 6 unwanetd null elements (one
> per char before the "=").
> I was expectiing a single element list with arr[0] = "=".
>
> What's Up ? Is ther a clen way to prevent creating these unwanted
> elements?
In your example the string "abc=In" is being split using the expression
/[a-zA-Z0-9]/. That expression matches in the string at positions 0, 1, 2, 4
and 5 therefore split will produce a list of *six* elements:
$ perl -le'
$str = "abc=In";
print ++$x, ": <$_>" for split /[a-zA-Z0-9]/, $str, -1;
'
1: <>
2: <>
3: <>
4: <=>
5: <>
6: <>
Your example only shows four because split automatically discards any trailing
empty elements.
Even if you used a modifier /[a-zA-Z0-9]/+ with the expression you would still
get the empty element at the beginning of the string. To get just the data
you want without the empty elements you should use a global match instead:
$ perl -le'
$str = "abc=In";
print ++$x, ": <$_>" for $str =~ /[^a-zA-Z0-9]+/g;
'
1: <=>
John
--
Perl isn't a toolbox, but a small machine shop where you can special-order
certain sorts of tools at low cost and in short order. -- Larry Wall
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