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Re: Can't use string
by Joost (Canon) on Jan 31, 2008 at 20:59 UTC
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strict prevents this for good reasons.
Even ignoring that you can't use symbolic refs to lexical variables, you really really want to use a @row array instead.
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Re: Can't use string
by Fletch (Bishop) on Jan 31, 2008 at 20:56 UTC
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Yes, because you've used strict and you're trying to use a symbolic reference. That's kind of the point, it won't let you do that. Perhaps you should re-read the docs and figure out what you really want to do.
The cake is a lie.
The cake is a lie.
The cake is a lie.
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This is not helpful. "Hi, your program doesn't work. Read the manual."
Looks to me like s/he's trying to dynamically generate variable names, which is usually when a person should be thinking hash or array.
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Re: Can't use string
by ikegami (Patriarch) on Jan 31, 2008 at 21:55 UTC
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It sounds like you want an array.
use strict;
my @rows;
$rows[1] = 10;
my $val = 1;
my $row = $rows[$val];
print("$row\n");
If you're indexes are sparsed or strings, a hash would be more appropriate.
use strict;
my %rows;
$rows{1} = 10;
my $val = 1;
my $row = $rows{$val};
print("$row\n");
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Technically the OP is using a hash. A realy ugly hackish hash.
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Are you referring to the fact that a symbol table is a sort of hash and that the code results in a lookup of the package's symbol table?
If you start calling that a hash lookup, you must also call $_ in print("$_\n") a hash lookup — it's the same op — and the term becomes useless.
No, the OP *isn't* using a hash.
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Re: Can't use string
by rir (Vicar) on Jan 31, 2008 at 22:00 UTC
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use diagnostics can be helpful when diagnostic messages seem cryptic.
Be well,
rir | [reply]
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I didn't know it worked for strict errors (or any other errors), so I tried it out. Turns out the diagnostic is even more cryptic than the original message, and misleading in mentioning references in what it usually a need to use a hash or array.
>perl -e"use diagnostics; use strict; print ${'x'}"
Can't use string ("x") as a SCALAR ref while "strict refs" in use at -
+e line 1 (#1)
(F) Only hard references are allowed by "strict refs". Symbolic
references are disallowed. See perlref.
Uncaught exception from user code:
Can't use string ("x") as a SCALAR ref while "strict refs" in
+use at -e line 1.
at -e line 1
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Re: Can't use string
by stiller (Friar) on Feb 01, 2008 at 12:20 UTC
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Others have pointed to reasons why you get the error message. Let me try to guess what you want instead:
use strict; use warnings;
my %value_for;
$value_for{'row10'} = 1;
#
# later...
my $key = 'row' . 10;
print $value_for{$key};
If you want a hash, you have to give it a name, unless you make it an anonymus hash of course.
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