Can we use variable for pattern match and extraction

ask_chinna has asked for the wisdom of the Perl Monks concerning the following question:

I have to extract few lines from 16MB file. I wrote a funcion for this purpose.

The starting line looks like this "*|NET min_msb_led[0] 0.0103148PF" and the last line to be extracted is "blank line".

I enter the "min_msb_led[0]" from key board, function returned "/^\*\|NET\smin_msb_led\0\/". It looks ok for me.

Here is some stuff from my main program.



		. 
		.
		.

$net_extract = name_modify($net);
		. 
		.
		.


ABC: while (<IN1>)

  {
  #print "entered into while loop\n";
      if ($_ =~ $net_extract) 
        {
         $count = 1;
         print "hello\n";
        }
		.
		.
		.

Chinna

Comment on Can we use variable for pattern match and extraction

Replies are listed 'Best First'.
Re: Can we use variable for pattern match and extraction by kvale (Monsignor) on Jun 26, 2002 at 19:59 UTC
You are almost correct with the syntax; if you want to match a string against a regex, you will want to use `ABC: while () { #print "entered into while loop\n"; if ($_ =~ /$net_extract/) { $count = 1; print "hello\n"; }` [download] -Mark	[reply] [d/l]
Re: Re: Can we use variable for pattern match and extraction by Rex(Wrecks) (Curate) on Jun 26, 2002 at 20:17 UTC
And the other thing that might be what you want is: `ABC: while () { #print "entered into while loop\n"; if ($_ eq $net_extract) { $count = 1; print "hello\n"; }` [download] These are 2 quite different approaches though, kvale's will execute the loop if any part of `$_` matches `$net_extract`, whereas the in the code above the loop will only execute if `$_` and `$net_extract` match exactly. "Nothing is sure but death and taxes" I say combine the two and its death to all taxes!	[reply] [d/l] [select]
Re: Re: Can we use variable for pattern match and extraction by ask_chinna (Novice) on Jun 26, 2002 at 21:59 UTC
Mark, I am able to work now, with the following modifications. ^\*\\|NET\smin_msb_led\0\, look at I have removed the starting and endig slashes. then "if ($_ =~ $net_extract)". -Chinna	[reply]