chomp/defined question

[SgtB]

Just got the Llama book, and learning perl!!!
Got a quick question though....
Here's the script:

chomp ($var = <STDIN>);
if (defined($var)) {
print &quot;Input was $var\n&quot;;
} else {
print &quot;no input\n&quot;;

At user input, if I just hit Enter, doesn't that just create a newline? Shouldn't the chomp command make the $var = undef then?

If I do that though, I just get &quot;Input was &quot;

Might be a simple question, but I thought that chomp always got rid of the first newline. ________________________________________
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[Coderifous]

take away the defined() part. If the variable has been defined at all (even it it is null value) it will still count as defined. And here is a learning-curve-shortener:

$var = undef;
undef $var;

These two lines are different - that is - they do different things. The first line makes it so that $var is defined to have the null value. In this case, defined($var) returns true. The second line makes it like $var never existed. It is removed from the symbol table (I believe). And defined($var) returns false.

--jim * * * Merry Christmas and Happy New Year! * * *

( Don't touch that Red Flag link you crazy freak, it's just a holiday greeting! )

 

[tanderso]

What I like to do is this...

 if (defined $var && $var =~ /\S/) {...}

Then it first checks if it's defined, and if it is, then it checks that it contains non-space characters.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

 

[goBoating]

There is a real difference between being 'empty' and 'undefined'. A variable can exist and be empty and defined. 'hope this helps

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[SgtB]

Got it! Thanks for all the help! ________________________________________
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