Negative regular expression not working at end of string

[nithinpes]

I tried the following regular expression in script to extract lines not begining with capital letters and not ending with numbers.

 if ($str =~/^[^A-Z].+[^0-9]$/)       ## similarly /^[^A-Z].+\D$/
   {
    ######
   }
 

This didn't work. The pattern condition was applied only to begining of string. The lines returned contained both digits & non-digits at the end.

However, I could achieve the task as follows:

 if (($str !~ /^[A-Z]/)&&($str !~ /[0-9]$/))
   {
    ######
   }
 

But, I need to know why the previous expression didn't work. I understand the problem with using negative grammar for pattern matching. But, I am unable to find any conceptual/ logical error in the first expression.
To boil down the above query,

if(/^[^A-Z]/)
{ print $_; }
 

will successfully return lines not begining with capital letters, while

if(/[^0-9]$/)
{ print $_; }
 

fails to return lines not ending with digits.It returns all lines.

Any help would be greatly appreciated.

[KevinADC]

The end of string anchor "$" is supposed to match the pattern before any newline at the end of the string/line. And it does in this example:

while(<DATA>){
   print if ($_ !~ /[0-9]$/);
}
 
__DATA__
This is a test
This is a test 96
this is a test
this is a test 99
this is another test

The lines with digits on the end do not get printed. But when I change it to a negated character class the newline is not being ignored:

while(<DATA>){
   print if ($_ =~ /[^0-9]$/);
}
 
__DATA__
This is a test
This is a test 96
this is a test
this is a test 99
this is another test 

and all the lines are printed. But if I chomp() each line the ones with digits on the end are not printed:

while(<DATA>){
   chomp;
   print if ($_ =~ /[^0-9]$/);
}
 
__DATA__
This is a test
This is a test 96
this is a test
this is a test 99
this is another test

Evidently a negated character class tied to the end of the line/string does not ignore the record seperator (a newline in this case) and the match fails. I could not find this documented anywhere though.

[nithinpes]

Thanks a lot!
This concept is not documented in any of the books that I refered or in online references.