pattern match

[Venkatesh can....can...]

$var="{' venkat'}->{'no'}->{'yes'}";
i want to get the "yes" token;
if i use
$var=~/\{'( .* )\}$/
i get venkat'}->{'no'}->{'yes
how to get the "yes" token...

 

[Gunnar Hjalmarsson]

$var="{' venkat'}->{'no'}->{'yes'}";
i want to get the "yes" token;
if i use
$var=~/\{'( .* )\}$/
i get venkat'}->{'no'}->{'yes

No you don't. You get nothing, because that regex does not match.
However, with the /x modifier it matches and assigns the string you
mention to $1.

how to get the "yes" token...

One way:

$var =~ /.+{'(.+)'}$/;

 

[venkatesh.naughty]

No you don't. You get nothing, because that regex does not match.
However, with the /x modifier it matches and assigns the string you
mention to $1.


One way:

     $var =~ /.+{'(.+)'}$/;

@gunnar

thanks it works but how?
the first .+ is greedy know? it 'll match up to the end right?

 

[Gunnar Hjalmarsson]

thanks it works but how?
the first .+ is greedy know?
Yes.

it 'll match up to the end right?

No, it matches one or more characters as long as it can without
preventing the whole regex from matching; in this case up to and
including the second arrow.

Remember that greediness never affects whether a regex matches or not.
It just may affect _how_ the regex matches.

 

[Tad J McClellan]

@gunnar

[ it is bad manners to quote .sigs, please do not do that. ]

the first .+ is greedy know? it 'll match up to the end right?

Right.

But then the regex engine will notice that the match will fail,
so it "backtracks" and attempts the match again.

How Regexes Work:

http://perl.plover.com/Regex/article.html