perl problem

vinaytp · 06-18-2009, 07:23 AM

hi all.......

i am trying to match a pattern like alphanumeric. example
123.
ab3.
73aae.
here . should be at the end of the pattern ....

$mystring = "hello.World";
if($mystring =~ m/[a-zA-Z0-9]+\. /)
{
print "Yes";
}

this is not working and also how to get the matched pattern in a variable...

can anyone please help me...

Thanks in advance....

ghostdog74 · 06-18-2009, 07:33 AM

put a $ after the \.

crs_zxf · 06-18-2009, 07:52 AM

You just have an extra space between '.' and the final '/', delete it, and your pattern will be right, this may due to your carelessness I think.

BTW, if you use '/' as the delimiter, 'm' before the first '/' is unnecessary.

vinaytp · 06-18-2009, 08:07 AM

Quote:

Originally Posted by ghostdog74

put a $ after the \.

$mystring = "hello.World";
if($mystring =~ m/[a-zA-Z0-9]+\.$ /)
{
print "Yes";
}

this is what you are telling right...

it outputs nothing ..it should print yes if the pattern matches... please help me.......

vinaytp · 06-18-2009, 08:11 AM

Quote:

Originally Posted by crs_zxf

You just have an extra space between '.' and the final '/', delete it, and your pattern will be right, this may due to your carelessness I think.

BTW, if you use '/' as the delimiter, 'm' before the first '/' is unnecessary.

you are correct..thanks a lot ..it works ...but i am not getting how to get the matched pattern in a seperate variable

crs_zxf · 06-18-2009, 08:41 AM

Oh! Sorry, I forgot to answer that question.

You can write your code like this:

$mystring = "hello.World";
if ($mystring =~ /([a-zA-Z0-9]+\.)/)
{
print $1, "\n";
print "Yes";
}

and you'll see "hello." on the screen.

Notice that I put parentheses around the patten, and every time you do this, Perl will automatically put the matched part of the string into internal variables like $1, $2, ... and there are as many of these variables as pairs of parentheses

vinaytp · 06-18-2009, 09:30 AM

Quote:

Originally Posted by crs_zxf

Oh! Sorry, I forgot to answer that question.

You can write your code like this:

$mystring = "hello.World";
if ($mystring =~ /([a-zA-Z0-9]+\.)/)
{
print $1, "\n";
print "Yes";
}

and you'll see "hello." on the screen.

Notice that I put parentheses around the patten, and every time you do this, Perl will automatically put the matched part of the string into internal variables like $1, $2, ... and there are as many of these variables as pairs of parentheses

Thank you very much once again....its working..can you please suggest me a good tutorial for regular expressions and parsing in perl......

Su-Shee · 06-18-2009, 09:36 AM

Just call perldoc perlrequick and perldoc perlretut - it's all there.

chrism01 · 06-18-2009, 07:10 PM

http://perldoc.perl.org/index-tutorials.html
http://www.perlmonks.org/?node=Tutorials

crs_zxf · 06-19-2009, 08:02 AM

Quote:

Originally Posted by vinaytp

Thank you very much once again....its working..can you please suggest me a good tutorial for regular expressions and parsing in perl......

You can refer to a book called "learning perl" (aka Llama book), I think this is a excellent book to start, and there are 3 chaps in this book talking about regular expression from level zero.