To my understanding, "$_" is the default input of the current running script/program, hence, if you overwrite $_ in an inner loop, it will overwrite $_ for the whole process. If you do not want to overwrite it, you'll need to assign $_ to a scalar before entering the loop that will overwrite $_.
Does that help or am I way off base? Johnny Roche Associate, Help Desk Harvard Management Company Tel: 617-720-6827 Fax: 617-878-6827 Email: roc...@hmc.harvard.edu -----Original Message----- From: Odin Liu [mailto:odinushu...@gmail.com] Sent: Friday, December 03, 2010 11:26 AM To: Shawn H Corey; beginners@perl.org Subject: Re: A strange problem with array outside I/O Interesting. So if I need deal with an array of files, and I have to use the array after reading each file. I have to save another copy of the array? Anyway, thanks for helping. On Sat, Dec 4, 2010 at 12:16 AM, Shawn H Corey <shawnhco...@gmail.com>wrote: > On 10-12-03 11:12 AM, Odin Liu wrote: > >> Still confusing. We know that inner loop's $_ overwrite the outer loop's >> $_ only in the inner loop. When the inner loop was over, the $_ would be >> it was in outer loop before the inner loop begin. Outer $_ would be >> restored by Perl automatically. >> >> But why this behavior changes when the inner loop is a diamond >> operation? If it is a Perl syntax, then how can I open a list of file, >> read their content, and then keep the file name list as it was? >> > > No, the behaviour is different because the inner loop is a while one. A > local copy of $_ would be made if the inner loop was another foreach one. > > > > -- > Just my 0.00000002 million dollars worth, > Shawn > > Programming is as much about organization and communication > as it is about coding. > > The secret to great software: Fail early & often. > > Eliminate software piracy: use only FLOSS. > -- *Odin Liu * RD Engineer work mail: liuyid...@baidu.com blog: http://blog.odichy.org/ profile: https://www.google.com/profiles/odinushuaia The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorized. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
