"switch$ia" but don't interpolate trailing "a"

ybiC has asked for the wisdom of the Perl Monks concerning the following question:

The following snippet is intended to iterate through my Cisco LAN switches to do stuff with each one. My naming convention is switchNNNa, where NNN is a 3digit number greater than 100 and the last character is always the letter a.

But the "a" following the device number is tripping me up. Perl thinks I mean "$ia" instead of "$i"a with this error: Global symbol "$ia" requires explicit package name at line 5

Suggestions from Wiser Monks? Perl 5.00503 on Debian 2.3r3, in case it matters.
    cheers,
    Don
    striving toward Perl Adept
    (it's pronounced "why-bick")

#!/usr/bin/perl -w
use strict;
my $i = 100;
for ($i..$i+200) {
   my $host = "switch$ia";
   print "$host\n";
   $i++;
}
[download]

Comment on "switch$ia" but don't interpolate trailing "a" Download Code

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Re: "switch$ia" but don't interpolate trailing "a" by jeroenes (Priest) on Oct 10, 2001 at 21:01 UTC
Not that I am wiser, but: `my $host = "switch${i}a";` [download] does the trick.	[reply] [d/l]
Re: Re: "switch$ia" but don't interpolate trailing "a" by mandog (Curate) on Oct 10, 2001 at 21:08 UTC
This also works `my $host = "switch$i".'a';` [download] email: mandog	[reply] [d/l]
(tye)Re: "switch$ia" but don't interpolate trailing "a" by tye (Sage) on Oct 10, 2001 at 21:44 UTC
My favorite is `"switch$i$,a"`. (: - tye (but my friends call me `"$,T$,y$,e$,"`)	[reply] [d/l] [select]
Re: "switch$ia" (Russ: Useless Benchmarking again) by Russ (Deacon) on Oct 10, 2001 at 21:16 UTC
I have to assume someone has done this before, but I didn't see it, so... Benchmarking interpolated strings vs. appended strings: `use Benchmark; timethese( 1000000, { interp => sub {my $R = 1; my $S = "Test${R}a"}, append => sub {my $R = 1; my $S = 'Test' . $R . 'a'} });` [download] results in: `Benchmark: timing 1000000 iterations of interp, manual... interp: 4 wallclock secs ( 3.68 usr + 0.05 sys = 3.73 CPU) @ 2680 +96.51/s manual: 3 wallclock secs ( 3.79 usr + -0.13 sys = 3.66 CPU) @ 2732 +24.04/s` [download] Slightly faster to append strings together than to interpolate them, but statistically, it's a wash... Russ Brainbench 'Most Valuable Professional' for Perl	[reply] [d/l] [select]
Re: Re: "switch$ia" (Russ: Useless Benchmarking again) by echo (Pilgrim) on Oct 10, 2001 at 21:19 UTC
Someone please correct me if I'm wrong, ISTR interpolated strings are converted to concatenation at compile time?	[reply]
Re: Re: Re: "switch$ia" (Russ: Useless Benchmarking again) by Fletch (Bishop) on Oct 10, 2001 at 21:29 UTC
You are correct, at least according to the `B::Deparse` documentation. Interpolation is just syntactic sugar for concatenation. You can see it for yourself: `$ perl -MO=Deparse,-p,-q -e '$foo = "BAR"; $bar = "a${foo}c"; $baz="a" +.$foo."c"' ($foo = 'BAR'); ($bar = (('a' . $foo) . 'c')); ($baz = (('a' . $foo) . 'c'));` [download] Update: Added concatenation to the example for comparison. Also, the output using `B::Terse` to dump the opcode tree may be more convincing.	[reply] [d/l]
Re:(3) "switch$ia" (Russ: Really Useless Benchmarking) by Russ (Deacon) on Oct 10, 2001 at 21:33 UTC
<sheepish grin> hehehe You're probably right. So, in the spirit of further useless benchmarking: `use Benchmark; timethese( 10000000, { 5 => sub {my $R = 5;}, 6 => sub {my $R = 6;} });` [download] results in: `5: 6 wallclock secs ( 6.61 usr + -0.03 sys = 6.58 CPU) @ 1519756 +.84/s 6: 6 wallclock secs ( 5.89 usr + 0.08 sys = 5.97 CPU) @ 1675041 +.88/s` [download] As you can see, it is slightly faster to assign a 6 than a 5, so I will use 6's more often from now on... :-) </sheepish grin> Russ Brainbench 'Most Valuable Professional' for Perl	[reply] [d/l] [select]