regular expressions

[safra]

Hi,

I can't get this to work. I simply like to return all characters in front of '>' in a string to a new string.

I tried it with $& which worked in a simple testing script but not in the actual script where I have to use it.

so I tried things like for example:
$original = "before>after";
$myString = $original;
$myString =~ /(^.*>)/;

it doesn't return anything!

Can anyone show me how to do this?

Thanks,
Ron

 

[justice41]

What you tried

$myString =~ /(^.*>)/;

only matches what you are looking for, it doesn't remove it. For that you need s///

$mystring =~ s/^.*?>//;

I added the '?' because it matches a little faster. It will find the first '>' instead of greedily matching everything up to the last '>'. So for the string 'before>middle>after' with the '?' would remove 'before>', but without the '?' would remove 'before>middle>'.

jaa

 

[vgg]

hi,

You can use the following perl special variables,
$` ->stores whatever precedes the currently matched pattern
$& ->The pattern that you gave.
$' -> The characters that follow the given pattern.

So in your case,

$` will have "before"
$& will hold ">" and
$' will contain "after"


Note:Using the above variables is not very efficient.

But it will get you what you wanted.


regards,
VGG

 

[justice41]

Oops, slight modification...

$myString =~ s/>.*?$//;

that will remove the '>' and everything after it, leaving $myString == 'before'. (I misread what you wanted to keep).

jaa

 

[safra]

thanks justice41, that worked!

VGG, I struggled with your solution. I can't get the matching to work. I assume I first have to look for the first '>' in the string. Nothing works,$' and $& are always empty and $' contains the complete string.

thanks,
Ron

 

[vgg]

Yes thats right.
Specify the pattern as />/ and check.
I am presently not on a PERL assignment so I am
helpless in testing the solution.

VGG