«

When running the following example:

$str="aaaaaa bbbb";
($a,$b)= $str=~/(\w+)\s?(\w+)/;
print $a,"\n",$b;

The result is:

aaaaa
a

Why do we get this result??? Can anybody explain it?
thanks and regards,
Ahmad

On Jan 2, 2:58*am, Ahmad <ahmad.abdulgh...@gmail.com> wrote:
> When running the following example:
>
> $str="aaaaaa * bbbb";
> ($a,$b)= $str=~/(\w+)\s?(\w+)/;
> print $a,"\n",$b;
>
> The result is:
>
> aaaaa
> a
>
> Why do we get this result??? Can anybody explain it?

Christian already explained to you the difference between ? and +, but
perhaps you were also (or rather) confused about what \s actually is.
You may be thinking that \s means simply "whitespace". It actually
means "any single white-space character". It is any ONE character
from the group: space, tab, newline, carriage return, or vertical
tab. If you want to match more than one character in sequence, you
must use the quantifiers (+, or *, or {n}, depending on your needs)

Hope that helps,
Paul Lalli

Ahmad <> wrote:
>When running the following example:
>
>$str="aaaaaa bbbb";
>($a,$b)= $str=~/(\w+)\s?(\w+)/;
>print $a,"\n",$b;
>
>The result is:
>
>aaaaa
>a
>
>Why do we get this result???

What did you expect instead?

jue

Paul Lalli wrote:
> On Jan 2, 2:58 am, Ahmad <ahmad.abdulgh...@gmail.com> wrote:
>> When running the following example:
>>
>> $str="aaaaaa bbbb";
>> ($a,$b)= $str=~/(\w+)\s?(\w+)/;
>> print $a,"\n",$b;
>>
>> The result is:
>>
>> aaaaa
>> a
>>
>> Why do we get this result??? Can anybody explain it?
>
> Christian already explained to you the difference between ? and +, but
> perhaps you were also (or rather) confused about what \s actually is.
> You may be thinking that \s means simply "whitespace". It actually
> means "any single white-space character". It is any ONE character
> from the group: space, tab, newline, carriage return, or vertical
> tab.

Perl doesn't use the vertical tab. That should be the group: space,
horizontal tab, new line, carriage return or form feed.


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

Ahmad wrote:

> When running the following example:
>
> $str="aaaaaa bbbb";
> ($a,$b)= $str=~/(\w+)\s?(\w+)/;
> print $a,"\n",$b;
>
> The result is:
>
> aaaaa
> a
>
> Why do we get this result??? Can anybody explain it?

(how you've used it) Like they've replied the ? simply makes the \s optional
as in it will match with or without \s in $str

(not how you've used it) Yet another or one more use (.+? and .*? only) (I
think) is to negate greed

$str="aaaaaa -bbbb -ccc";
($a,$b)= $str=~/(\w+).+?-(\w+)/; # negate greed
print $a,"\n",$b;
($a,$b)= $str=~/(\w+).+-(\w+)/;
print "\n\n", $a,"\n",$b, "\n";
# end

--
AC