'use of uninitialised value' error message

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

Dear Monks,

Why does


my $file_name = "$sorted_files[0]";
[download]

Give me a 'use of uninitialised value' error message, but the following does not:


my $file_name = $sorted_files[0];
[download]

Comment on 'use of uninitialised value' error message Select or Download Code

Replies are listed 'Best First'.
Re: 'use of uninitialised value' error message by GrandFather (Saint) on Apr 12, 2006 at 10:19 UTC
Because the former interpolates a variable into a string which involves stringising the variable and that fails if the variable is not defined. The latter is simply copying the contents of a variable that happens to be undef into another variable. No interpretation of the contents of the variable required so no error. DWIM is Perl's answer to Gödel	[reply]
Re: 'use of uninitialised value' error message by graq (Curate) on Apr 12, 2006 at 11:59 UTC
Because in the first snippet you are making use of the value of `$sorted_files[0]` and in the second you are not. -=( Graq )=-	[reply] [d/l]