how to pass argparse arguments to a class

Question

I'm very new to coding in general and Python in particular. I'm trying to learn how to pass argparse arguments I have created into a class for use the right/recommend way. In addition to learning python, I'm trying to learn how to do things in an OOP manner so that learning other, OOP-type languages comes a bit easier.

So here's a sample of what I am trying to do:

import argparse  class passyourcliargstome():     def __init__(self, whatdoiputheretogetmycliargs):         #how do I get my cli args here?         pass     def otherfunctionsthatdothings():         pass  if __name__ == '__main__':     #grab the arguments when the script is ran     parser = argparse.ArgumentParser(          description='Make things happen.')     parser.add_argument('-f', '--foo', action='store_true', default=False, help='here be dragons')     parser.add_argument('-b', '--bar', action='store_true', default=False, help='here be more dragons')      passyourcliargstome.otherfunctionsthatdothings() 

So, I'm defining argparse arguments outside of the main class, and want to know how to get them inside the class. Is this even the right way to do it? should I just make argparse a function under my class?

Thank you in advance for any assistance, references, etc.

Edit: 11/16 2:18 EST

Note: Since I don't have enough rep to answer my own question, this is my only recourse for posting a proper answer.

Okay, it took me some doing, but I managed to piece this together. RyPeck's answers helped me in getting my arguments (something my code was missing), but then afterwards I was getting unbound method errors When I was trying to test the code. I had no idea what that meant. Did I mention that I live up to my screen name?

It didn't really click until I found and read this. Here is my working code. If anyone has anything to add to this, up to and including "You're still doing it wrong, do it this way, the right way." I'm all ears. In the meantime, thanks for your help.

import argparse  class Passyourcliargstome(object):      def __init__(self):         #here's how I got my args here         self.foo = args.foo         self.bar = args.bar     def otherfunctionsthatdothings(self):         print "args inside of the main class:"         print self.foo         print self.bar  if __name__ == '__main__':     #grab the arguments when the script is ran     parser = argparse.ArgumentParser(description='Make things happen.')     parser.add_argument('-f', '--foo', action='store_true', default=False, help='here be dragons')     parser.add_argument('-b', '--bar', action='store_true', default=False, help='here be more dragons')      args = parser.parse_args()     print "args outside of main:"     print args.foo     print args.bar      #this was the part that I wasn't doing, creating an instance of my class.     shell = Passyourcliargstome()     shell.otherfunctionsthatdothings() 

Running this code with no arguments prints False four times. two times outside of the class instance, two times within the class instance.

Answer 1

Use parser.parse_args and wrap it with vars to convert the special argparse Namespace type to a regular Python dict. In general, you want this pattern:

def main():   parser = argparse.ArgumentParser()   parser.add_argument('foo')   parser.add_argument('bar')   args = parser.parse_args()   args_dict = vars(args) 

After that, you can pass arguments explicitly or all at once to whatever class or function will take it. For a class, it is best to write the required arguments explicitly. Like so:

class MyClass(object):   def __init__(self, foo, bar):     self.foo = foo     self.bar = bar    def Print(self):     print self.foo     print self.bar 

Now you can put those two together like this:

import argparse  class MyClass(object):   def __init__(self, foo, bar):     self.foo = foo     self.bar = bar    def Print(self):     print self.foo     print self.bar  def main():   parser = argparse.ArgumentParser()   parser.add_argument('foo')   parser.add_argument('bar')   args = parser.parse_args()   c1 = MyClass(args.foo, args.bar)   args_dict = vars(args)   c2 = MyClass(**args_dict) 

Both c1 and c2 will be created. Best approach, though, is to create classes explicitly, as is done with c1.