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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.
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Instance variables of numerical type (int, double, etc.) are automatically initialized to zero if you provide no other values; boolean variables are initialized to false; and char variables, to the Unicode character with code number zero. An instance variable can also be a variable of object type.
For Python 3.7+ you can use a Data Class, which is a very pythonic and maintainable way to do what you want. It allows you to define fields for your class, which are your automatically initialized instance variables.
Java does not initialize non-array local variables (also referred to as automatic variables) . The Java compiler generates error messages when it detects attempts to use uninitialized local variables. The Initializer program shows how automatic initialization works.
A constructor is typically used to initialize instance variables representing the main properties of the created object.
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' If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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