When I pass a variable through a couple of subs, it always turns up empty. Why is this ?
sub Main {
my $myVariable = "Test string";
firstSub($myVariable);
}
sub firstSub {
my($myVariable) = @_;
my @array = `some command`;
secondSub(@array, $myVariable);
}
sub secondSub {
my(@array, $myVariable) = @_;
print $myVariable;
}
echo will be undef.
echo is not a valid Perl function. You're confusing shells with Perl here. Try "print" or "say" (the latter with Perl 5.10 and newer).
Also you cannot assign an array & a scalar variable to another array & scalar variable. Meaning this won't work because all of the elements of the right-hand side will be assigned to the array on left-hand side, and nothing will be assigned to the scalar: my (@array, $myVariable) = @_; Either swap the order of the elements my ($myVariable, @array) = @_; (also when calling the function) or use array references instead of full arrays.
Your code doesn't do anything because you have defined three subroutines, but you have never called them.
Just add Main(); to actually run your main sub.
Also, you need print instead of echo.
Also, the passing of variables is incorrect, as Moritz Bunkus explained.
Main and using echo instead of print. I assumed that you must have never called Main, because otherwise you would get an error that echo is not a function (the issue has now been confused by edits to your question). The moral of the story is, always post a complete code example with your question, and always test your own example before you post it.When you call secondsub() the @array and the $myVariable is being sent as a list(a single element) and is been assigned to @array in the secondsub function. You can see both the @array and $myVariable values when you print @array in secondsub.
You have to pass the array as a reference and receive it as a scalar value in secondsub. The below code will work.
&Main();
sub Main {
my $myVariable = "Test string";
firstSub($myVariable);
}
sub firstSub {
my($myVariable) = @_;
my @array = `some command`;
secondSub(\@array,$myVariable);
}
sub secondSub {
my($ref,$myVariable) = @_;
print $myVariable;
}
Passing varibles:
my $txt = "this text for sample"; Function_Passing_varible($txt); sub Function_Passing_varible{ my $text = shift; print $text; }
I think you like this answer......
echois no perl function. ALways adduse strict;anduse warnings;to your scripts.@array? Your first code was correctly passing the variables into the function. Now you have confused the issue by adding another problem after your original problem was answered.