[EMAIL PROTECTED] a écrit : > I started using Python a couple of days ago - here are a few > questions: > > * Doesn't the __main__() method automatically execute when I run my > python program?
Which "__main__" method ??? Anyway, the answer is no. Every code at the top-level (which includes import, class and def statements...) is executed when the module is first loaded - whether as a proper module (ie: imported from somewhere else) or as a main program (ie-> python mymodule.py). In the first case, the special variable __name__ is set to the module's name, in the second to '__main__'. So you can rely on this to have code executed when the module is used as a program. The usual idiom is # mymodule.py (imports here) (classes and defs here) def main(argv): (code of main function here) return 0 if __name__ == '__main__': import sys sys.exit(main(sys.argv)) > * Only when I do an import of my test.py file within python and then > run test.__main__() BTW, you should *not* use names with 2 leadings and 2 trailing underscores. These names are reserved for Python implementation stuff. > I can see where my bugs are. Is this correct? Nope. You can also spot bugs by reading the code or running it thru the debugger !-) More seriously : using the above idiom (or any variant of - the important part being the conditional on __name__ == '__main__'), you can just $ python mymodule.py to run your program. > (right now this is my only way of running my python program and see > where I have problems) > * Once I've done an import and then I wish to make a change to the > file I've imported I have to quit Python, restart and import that > module again in order for the module to be refreshed. Is there no "re- > import" ? reload(module_object) But it's of very limited use. The best thing to do is usually to have a simple test file that setup the desired state (imports etc) that you execute after each change, passing the -i option to the python interpreter (this will leave the interpreter in interactive mode after execution of the test file, so you can inspect your objects, test things etc). > * Finally, could someone tell me why I'm having problems with the > small module below? > - Python pretends I provide chassis_id() with three parameters, even > though I clearly only provide it with two - why? Without even reading the code, I can tell you it's an instance or classmethod with either a wrong declaration or wrongly called. > > #!/usr/bin/python > import scapy > import struct > > class lldp_class: Do yourself a favor: use new-style classes. Also, it would be better to stick to usual naming conventions (Python relies heavily on conventions): http://www.python.org/dev/peps/pep-0008/ class Lldp(object): > def __init__(self): > self.chassis_id_tlv = None > > def chassis_id(subtype, chassis_info): Bingo. You need to have self as the first argument. The instance is passed as the first argument of a method. def chassis_id(self, subtype, chassis_info): > if subtype == 4: > chassis_data = struct.pack("!B",chassis_info) > subtype_data = struct.pack("!B",subtype) > self.chassis_id_tlv = subtype_data + chassis_data > > def __main__(): def main(): > p = lldp_class() > p.chassis_id(4, "01:80:C2:00:00:0E") For the record: this is interpreted as: lldp_class.chassis_id(p, 4, "01:80:C2:00:00:0E") > payload = p.chassis_id_tlv > ether = scapy.Ether(dst="01:02:03:04:05:06") > fullpayload = ether + payload > sendp(fullpayload) > if __name__ == '__main__': main() As a side note, it looks like there are a couple point where your design may be improved. Like passing subtype and chassis_info to the __init__ of your class. HTH -- http://mail.python.org/mailman/listinfo/python-list
