The first lien makes sure that subsequently $b will not be defined anymore. THis is necessary whenyou are somehow using the variable $b in subsequent lines but wanna make sure that there is no previous values to corrupt it.
i have seen it used in a lopp where $b is a global variable for example and is used in a loop ... but each iteration of hte lopp wneeds a fresh copy of $b without its previous iterations value. all the code below does is to make sure $b is no longer defined and then it reads a line from the handler into $a and assign the chopeped value into $b. It then strips out all whitespace characters from $b. On Tue, Oct 23, 2001 at 01:38:31PM +0330, nafiseh saberi shaped the electrons to read: > thx a lot....and a lot... > can you understand it.. > > undef $b; > while > > $a=<THEFILE>; #the name of handler's file > chop; > $b=$a; > $b=~s/\s+//g; > } > thx again. > __________________________________ > Best regards ......... Nafiseh Saberi > Iran ......... > notes ......... > Pray for Afghans people. > Clothes , dont make the man. > www.iraninfocenter.net > www.sorna.net > ___________________________________ > ----- Original Message ----- > From: "Rex Arul" <[EMAIL PROTECTED]> > To: "nafiseh saberi" <[EMAIL PROTECTED]> > Sent: Tuesday, October 23, 2001 13:36 PM > Subject: Re: undef function > > > > undef as an operator is very useful to "free-up" tied resources like > > objects, database recordsets, connection objects or even ordinary arrays > and > > hashes. > > > > It is almost the same as > > objRs = null (VBScript) > > objRS = null ;(JavaScript) > > undef($objRS); (Perl) > > > > > > ----- Original Message ----- > > From: "nafiseh saberi" <[EMAIL PROTECTED]> > > To: "Rex Arul" <[EMAIL PROTECTED]> > > Sent: Tuesday, October 23, 2001 5:53 AM > > Subject: Re: undef function > > > > > > > can u explain more.... > > > e.g the main usage of it...? > > > __________________________________ > > > Best regards ......... Nafiseh Saberi > > > Iran ......... > > > notes ......... > > > Pray for Afghans people. > > > Clothes , dont make the man. > > > www.iraninfocenter.net > > > www.sorna.net > > > ___________________________________ > > > ----- Original Message ----- > > > From: "Rex Arul" <[EMAIL PROTECTED]> > > > To: <[EMAIL PROTECTED]>; "nafiseh saberi" > > <[EMAIL PROTECTED]> > > > Cc: "perl" <[EMAIL PROTECTED]> > > > Sent: Tuesday, October 23, 2001 13:24 PM > > > Subject: Re: undef function > > > > > > > > > > > > > > $val = undef; #undef is more like a value here. > > > > > > > > undef ($objRS); #undef is more of a function here > > > > undef(%hash); #and here too > > > > > > > > -- Rex > > > > > > > > ----- Original Message ----- > > > > From: <[EMAIL PROTECTED]> > > > > To: "nafiseh saberi" <[EMAIL PROTECTED]> > > > > Cc: "perl" <[EMAIL PROTECTED]> > > > > Sent: Tuesday, October 23, 2001 5:58 AM > > > > Subject: Re: undef function > > > > > > > > > > > > > undef is not really a function ... delete is ... > > > > > undef is (although many might disagree with me) more like a value > not > > > > unlike > > > > > 1,2 or 'cowabunga' that just says there is no value (hope this makes > > > > sense) > > > > > > > > > > but when u set a hash to undef it effectively deletes the hash from > > > > existance > > > > > ... (again i might be wrong about this one) > > > > > > > > > > On Tue, Oct 23, 2001 at 10:39:50AM +0330, nafiseh saberi shaped the > > > > electrons to read: > > > > > > > > > > > > > > > > > > hi all... > > > > > > I read about "undef" a lot > > > > > > but.. > > > > > > I dont understand the difference between "undef" and "delete".. ? > > > > > > and why do we use undef... > > > > > > thx > > > > > > __________________________________ > > > > > > Best regards ......... Nafiseh Saberi > > > > > > Iran ......... > > > > > > notes ......... > > > > > > Pray for Afghans people. > > > > > > Clothes , dont make the man. > > > > > > www.iraninfocenter.net > > > > > > www.sorna.net > > > > > > ___________________________________ > > > > > > > > > > -- > > > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > -- > > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > -- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
