vj wrote:
> I posted too soon:
>
>> Statement 1:
>> my $today = sprintf("%4s%02s%02s", [localtime()]->[5]+1900,
>> [localtime()]->[4]+1, [localtime()]->[3]) ;
>
> 1. is localtime the same as time in python?
http://perldoc.perl.org/functions/localtime.html
It's more like time.localtime()
One key thing you'll notice here is the adding of 1900 - the year returned by
Perl's localtime is 'number of years since 1900' so in order to convert it to
the actual year you have to add 1900.
> 2. What does -> ? do in perl?
In this case, it's accessing localtime similar to something like localtime[5].
-> can basically be considered similar to dotted notation in Python, used to
access items in a container object.
> 3. What is 'my'
http://perldoc.perl.org/functions/my.html
It's a way of declaring a local variable in Perl.
>> Statement 2:
>> my $password = md5_hex("$today$username") ;
>
> is md5_hex the same as md5.new(key).hexdigest() in python?
http://www.xav.com/perl/site/lib/Digest/MD5.html#functions
>> $msglen = bcdlen(length($msg)) ;
>
> 1. here the funciton is being called with the length of variable msg.
> However the function def below does not have any args
>
>> sub bcdlen {
>> my $strlen = sprintf("%04s", shift) ;
>> my $firstval = substr($strlen, 2, 1)*16 + substr($strlen, 3, 1) ;
>> my $lastval = substr($strlen, 0, 1)*16 + substr($strlen, 1, 1) ;
>> return chr($firstval) . chr($lastval) ;
>>
>> }
Perl subroutines (functions) can be declared without any arguments if desired,
and then you can use 'shift' to access any arguments. So:
sub printMe {
my $arg = shift;
print $arg;
}
would print the first argument passed to it, e.g. printMe("foo"); would output
foo.
>
> 2. What does shift do above?
http://perldoc.perl.org/functions/shift.html
See above, it's used for accessing the first value of an array, in this case an
arry of arguments to a subroutine.
> 3. is the '.' operator just + in python?
'.' operator is used for string concatenation in Perl, so + would be the
equivalent in Python, yes.
-Jay
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