Automatically initialize instance variables?

Question

I have a python class that looks like this:

class Process:     def __init__(self, PID, PPID, cmd, FDs, reachable, user): 

followed by:

        self.PID=PID         self.PPID=PPID         self.cmd=cmd         ... 

Is there any way to autoinitialize these instance variables, like C++'s initialization list? It would spare lots of redundant code.

Answer 1

You can use a decorator:

from functools import wraps import inspect  def initializer(func):     """     Automatically assigns the parameters.      >>> class process:     ...     @initializer     ...     def __init__(self, cmd, reachable=False, user='root'):     ...         pass     >>> p = process('halt', True)     >>> p.cmd, p.reachable, p.user     ('halt', True, 'root')     """     names, varargs, keywords, defaults = inspect.getargspec(func)      @wraps(func)     def wrapper(self, *args, **kargs):         for name, arg in list(zip(names[1:], args)) + list(kargs.items()):             setattr(self, name, arg)          for name, default in zip(reversed(names), reversed(defaults)):             if not hasattr(self, name):                 setattr(self, name, default)          func(self, *args, **kargs)      return wrapper 

Use it to decorate the __init__ method:

class process:     @initializer     def __init__(self, PID, PPID, cmd, FDs, reachable, user):         pass 

Output:

>>> c = process(1, 2, 3, 4, 5, 6) >>> c.PID 1 >>> dir(c) ['FDs', 'PID', 'PPID', '__doc__', '__init__', '__module__', 'cmd', 'reachable', 'user'