© # -*- coding: utf-8 -*- © # Python © © # in Python, one can define a boxed set © # of data and functions, which are © # traditionally known as "class". © © # in the following, we define a set of data © # and functions as a class, and name it xxx © class xxx: © "a class extempore! (^_^)" © i=1 # i'm a piece of data © def okaydokey(self): return "okaydokey" © def square(self,a): return a**a © © # in the following, © # we create an object, of the class xxx. © # also known as "instantiate a class". © x = xxx() © © # data or functions defined in a class © # are called the class's attributes or © # methods. © # to use them, append a dot and © # their name after the object's name. © print 'value of attribute i is:', x.i © print "3 squared is:", x.square(3) © print "okaydokey called:", x.okaydokey() © © # in the definition of function inside a © # class, the first parameter "self" is © # necessary. (you'll know why when you need to) © © # the first line in the class definition © # is the class's documentation. It can © # be accessed thru the __doc__ © # attribute. © print "xxx's doc string is:", x.__doc__ © © # one can change data inside the class © x.i = 400 © © # one can also add new data to the class © x.j=4 © print x.j © © # or even override a method © x.square = 333 © # (the following line will no longer work) © # print "3 squared is:", x.square(3) © © # in Python, one must be careful not to © # overwrite data or methods defined in a © # class.
---------------------- for a obfuscated treatment with a few extra info, see http://python.org/doc/2.3.4/tut/node11.html in Python terminal, type help() then topic CLASSES to read about existing datatypes as classes, and classes in Python try to write a class with one data of integer and two functions, one increases it by 1, one decreases it by 1. note: inside a class definition, to refer to data inside itself use self. e.g. self.i ------------------------------------------ Perl does not support classes or objects in the so-called "Object Oriented" programing. However, a complete set of emulations of OO style of programing have been done, resulting in modules and books and many documentations and tutorials. here is a quote from perldoc perlobj First you need to understand what references are in Perl. See perlref for that. Second, if you still find the following reference work too complicated, a tutorial on object-oriented programming in Perl can be found in perltoot and perltooc. it goes on and sayz: If you're still with us, then here are three very simple definitions that you should find reassuring. 1. An object is simply a reference that happens to know which class it belongs to. 2. A class is simply a package that happens to provide methods to deal with object references. 3. A method is simply a subroutine that expects an object reference (or a package name, for class methods) as the first argument. Good luck. Note: this post is from the Perl-Python a-day mailing list at http://groups.yahoo.com/group/perl-python/ to subscribe, send an email to perl-python-subscribe @ yahoogroups.com if you are reading it on a web page, program examples may not run because html conversion often breaks the code. Xah [EMAIL PROTECTED] http://xahlee.org/PageTwo_dir/more.html -- http://mail.python.org/mailman/listinfo/python-list
