Array is empty when using if else condition

kaka_2 has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks

I am not getting why i am getting an empty array when using if else condition.

i have a simple script as below.

#!/usr/bin/perl


my $SP4binconfig = "/etc/SPECdaemons.list";
open (my $fh, '<', $SP4binconfig) or die "cant open the file : $!";
        my @SPECores = <$fh>;
        close $fh;

print "@SPECores";
[download]

this script print the array correctly. but when i use the same codes with If Else condition it does not and i cant figure out what is wrong with this

#!/usr/bin/perl


my $SP4binconfig = "/etc/SPECdaemons.list";
if (-e $SP4binconfig)
{
open (my $fh, '<', $SP4binconfig) or die "cant open the file : $!";
        my @SPECores = <$fh>;
        close $fh;
}
else
{
print "mmmmm";
}

print "@SPECores";
[download]

Could someone help?

Comment on Array is empty when using if else condition Select or Download Code

Replies are listed 'Best First'.
Re: Array is empty when using if else condition by AppleFritter (Vicar) on Aug 28, 2014 at 11:39 UTC
To expand on what flexvault said: you're using `@SPECores` as both a lexical and a global variable. The lexical declaration (`my @SPECores`) in your `if() { ... }` block shadows the global variable, so you're writing to the lexical variable, but when it goes out of scope at the end of the block, the global variable becomes visible again, and that's what you print. `use strict;` might've given you a clue here, BTW: `Global symbol "@SPECores" requires explicit package name at 1098850.pl + line 17. Execution of 1098850.pl aborted due to compilation errors.` [download] Always `use strict`. It's your friend, and will catch many mistakes and potential sources of headaches for you.	[reply] [d/l]
Re^2: Array is empty when using if else condition by jellisii2 (Hermit) on Aug 28, 2014 at 20:28 UTC
To expand, runrig's Use strict and warnings writeup is excellent reading and a jump off point for other commentary on error catching facilities offered in perl.	[reply]
Re^2: Array is empty when using if else condition by kaka_2 (Sexton) on Aug 28, 2014 at 14:25 UTC
Thank you both of you. I understand it now. -KAKA-	[reply]
Re: Array is empty when using if else condition by flexvault (Monsignor) on Aug 28, 2014 at 10:59 UTC
kaka_2, `my @SPECores = <$fh>;` [download] You must first define '@SPECores' before the 'if...else...'. Regards...Ed "Well done is better than well said." - Benjamin Franklin	[reply] [d/l]


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