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Groups > comp.lang.perl.misc > #8641
| From | Jim Gibson <jimsgibson@gmail.com> |
|---|---|
| Newsgroups | comp.lang.perl.misc |
| Subject | Re: this should work |
| Date | 2013-07-10 15:49 -0700 |
| Message-ID | <100720131549354102%jimsgibson@gmail.com> (permalink) |
| References | <krkm21$19jd$1@news.ntua.gr> |
In article <krkm21$19jd$1@news.ntua.gr>, George Mpouras
<nospam.gravitalsun.antispam@spamno.hotmail.anispam.com.nospam> wrote:
> foreach my $dir (qw/commands_pre commands_post/) {
> $dir = "/tmp/$dir";
> print "$dir\n"
> }
>
> # Modification of a read-only value attempted at ./test line 139
Because of the aliasing feature of foreach loops, you are trying to
modify the elements of qw/commands_pre commands_post/, which are not
lvalues. Try this instead:
#!/usr/bin/perl
use strict;
use warnings;
foreach my $dir (qw/commands_pre commands_post/) {
my $tmpdir = "/tmp/$dir";
print "$tmpdir\n"
}
See 'perldoc perlsyn' and the section entitled 'Foreach Loops':
"LABEL foreach VAR (LIST) BLOCK"
"If any element of LIST is an lvalue, you can modify it by modifying VAR
inside the loop. Conversely, if any element of LIST is NOT an lvalue,
any attempt to modify that element will fail. In other words, the
'foreach' loop index variable is an implicit alias for each item in the
list that you're looping over."
--
Jim Gibson
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this should work "George Mpouras" <nospam.gravitalsun.antispam@spamno.hotmail.anispam.com.nospam> - 2013-07-11 01:08 +0300
Re: this should work Jim Gibson <jimsgibson@gmail.com> - 2013-07-10 15:49 -0700
Re: this should work George Mpouras <nospam.gravitalsun.noadsplease@hotmail.noads.com> - 2013-07-11 09:42 +0300
Re: this should work tmcd@panix.com (Tim McDaniel) - 2013-07-11 08:02 +0000
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 12:45 +0100
Re: this should work George Mpouras <nospam.gravitalsun.noadsplease@hotmail.noads.com> - 2013-07-11 15:03 +0300
Re: this should work "Peter J. Holzer" <hjp-usenet3@hjp.at> - 2013-07-11 14:52 +0200
Re: this should work George Mpouras <nospam.gravitalsun.noadsplease@hotmail.noads.com> - 2013-07-11 16:01 +0300
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 14:29 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 14:27 +0100
Re: this should work Peter Makholm <peter@makholm.net> - 2013-07-11 15:50 +0200
Re: this should work Jürgen Exner <jurgenex@hotmail.com> - 2013-07-11 03:34 -0700
Re: this should work George Mpouras <nospam.gravitalsun.noadsplease@hotmail.noads.com> - 2013-07-11 13:55 +0300
Re: this should work Peter Makholm <peter@makholm.net> - 2013-07-11 13:57 +0200
Re: this should work Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid> - 2013-07-11 09:10 -0400
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 21:35 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 10:32 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 12:51 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 13:42 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 16:23 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 17:17 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 18:08 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 21:48 +0100
Re: this should work Keith Keller <kkeller-usenet@wombat.san-francisco.ca.us> - 2013-07-11 10:32 -0700
Re: this should work Jürgen Exner <jurgenex@hotmail.com> - 2013-07-11 10:48 -0700
Re: this should work "George Mpouras" <nospam.gravitalsun.antispam@spamno.hotmail.anispam.com.nospam> - 2013-07-11 21:38 +0300
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 23:08 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 18:48 +0100
Re: this should work Charles DeRykus <derykus@gmail.com> - 2013-07-11 12:03 -0700
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 22:02 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 23:06 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-12 01:04 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-15 13:41 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-15 14:07 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-15 15:05 +0100
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-15 21:02 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-15 23:58 +0100
Re: this should work tmcd@panix.com (Tim McDaniel) - 2013-07-15 17:23 +0000
Re: this should work Charlton Wilbur <cwilbur@chromatico.net> - 2013-07-15 15:40 -0400
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 21:58 +0100
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-11 23:17 +0100
[OT] scoping Ivan Shmakov <oneingray@gmail.com> - 2013-07-12 07:50 +0000
Re: [OT] scoping aka 'new holes in old shoes' Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-12 11:53 +0100
[OT] engineering Ivan Shmakov <oneingray@gmail.com> - 2013-07-15 11:37 +0000
Re: [OT] engineering Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-16 21:49 +0100
Re: [OT] engineering Ivan Shmakov <oneingray@gmail.com> - 2013-07-17 09:27 +0000
Re: [OT] engineering Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-17 15:53 +0100
Re: [OT] engineering Ivan Shmakov <oneingray@gmail.com> - 2013-07-22 10:36 +0000
Re: [OT] engineering Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid> - 2013-07-23 06:43 -0400
Re: [OT] engineering Ivan Shmakov <oneingray@gmail.com> - 2013-07-22 10:38 +0000
Re: [OT] engineering Rui Maciel <rui.maciel@gmail.com> - 2013-07-26 10:09 +0100
Re: [OT] scoping "Peter J. Holzer" <hjp-usenet3@hjp.at> - 2013-07-12 14:58 +0200
Re: [OT] scoping Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-12 15:50 +0100
Re: [OT] scoping Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid> - 2013-07-12 13:34 -0400
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-12 22:04 +0100
Re: [OT] scoping Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-13 13:13 +0100
Re: [OT] scoping John Black <jblack@nospam.com> - 2013-07-13 20:01 -0500
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-14 03:24 +0100
Re: [OT] scoping "Dr.Ruud" <rvtol+usenet@xs4all.nl> - 2013-07-14 10:49 +0200
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-14 13:13 +0100
Re: [OT] scoping "Dr.Ruud" <rvtol+usenet@xs4all.nl> - 2013-07-14 17:02 +0200
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-14 22:21 +0100
Re: [OT] scoping "Dr.Ruud" <rvtol+usenet@xs4all.nl> - 2013-07-15 02:21 +0200
Re: [OT] scoping Xho Jingleheimerschmidt <xhoster@gmail.com> - 2013-07-14 17:04 -0700
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-15 14:12 +0100
Re: [OT] scoping tmcd@panix.com (Tim McDaniel) - 2013-07-14 15:11 +0000
Re: [OT] scoping "Dr.Ruud" <rvtol+usenet@xs4all.nl> - 2013-07-14 17:34 +0200
Re: [OT] scoping Xho Jingleheimerschmidt <xhoster@gmail.com> - 2013-07-14 15:34 -0700
Re: [OT] scoping Ben Morrow <ben@morrow.me.uk> - 2013-07-15 14:27 +0100
Re: [OT] scoping John Black <jblack@nospam.com> - 2013-07-14 23:48 -0500
Re: [OT] scoping Martijn Lievaart <m@rtij.nl.invlalid> - 2013-07-13 12:14 +0200
Re: this should work David Harmon <source@netcom.com> - 2013-07-11 10:02 -0700
Re: this should work Ben Morrow <ben@morrow.me.uk> - 2013-07-11 22:04 +0100
Re: this should work David Harmon <source@netcom.com> - 2013-07-12 09:34 -0700
Re: this should work Rainer Weikusat <rweikusat@mssgmbh.com> - 2013-07-12 18:16 +0100
Re: this should work "Dr.Ruud" <rvtol+usenet@xs4all.nl> - 2013-07-12 15:44 +0200
Re: this should work David Harmon <source@netcom.com> - 2013-07-12 15:53 -0700
Re: this should work Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid> - 2013-07-11 09:14 -0400
Re: this should work "George Mpouras" <nospam.gravitalsun.antispam@spamno.hotmail.anispam.com.nospam> - 2013-07-11 19:45 +0300
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