FAQ 7.20 Why doesn't "my($foo) = <FILE>;" work right?
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From: PerlFAQ Server on 24 Feb 2010 18:00 This is an excerpt from the latest version perlfaq7.pod, which comes with the standard Perl distribution. These postings aim to reduce the number of repeated questions as well as allow the community to review and update the answers. The latest version of the complete perlfaq is at http://faq.perl.org . -------------------------------------------------------------------- 7.20: Why doesn't "my($foo) = <FILE>;" work right? "my()" and "local()" give list context to the right hand side of "=". The <FH> read operation, like so many of Perl's functions and operators, can tell which context it was called in and behaves appropriately. In general, the scalar() function can help. This function does nothing to the data itself (contrary to popular myth) but rather tells its argument to behave in whatever its scalar fashion is. If that function doesn't have a defined scalar behavior, this of course doesn't help you (such as with sort()). To enforce scalar context in this particular case, however, you need merely omit the parentheses: local($foo) = <FILE>; # WRONG local($foo) = scalar(<FILE>); # ok local $foo = <FILE>; # right You should probably be using lexical variables anyway, although the issue is the same here: my($foo) = <FILE>; # WRONG my $foo = <FILE>; # right -------------------------------------------------------------------- The perlfaq-workers, a group of volunteers, maintain the perlfaq. They are not necessarily experts in every domain where Perl might show up, so please include as much information as possible and relevant in any corrections. The perlfaq-workers also don't have access to every operating system or platform, so please include relevant details for corrections to examples that do not work on particular platforms. Working code is greatly appreciated. If you'd like to help maintain the perlfaq, see the details in perlfaq.pod. |