Python extension methods

Question

OK, in C# we have something like:

public static string Destroy(this string s) { 
    return "";
}

So basically, when you have a string you can do:

str = "This is my string to be destroyed";
newstr = str.Destroy()
# instead of 
newstr = Destroy(str)

Now this is cool because in my opinion it's more readable. Does Python have something similar? I mean instead of writing like this:

x = SomeClass()
div = x.getMyDiv()
span = x.FirstChild(x.FirstChild(div)) # so instead of this

I'd like to write:

span = div.FirstChild().FirstChild() # which is more readable to me

Any suggestion?

Answer 1

You can just modify the class directly, sometimes known as monkey patching.

def MyMethod(self):
      return self + self

MyClass.MyMethod = MyMethod
del(MyMethod)#clean up namespace

I'm not 100% sure you can do this on a special class like str, but it's fine for your user-defined classes.

Update

You confirm in a comment my suspicion that this is not possible for a builtin like str. In which case I believe there is no analogue to C# extension methods for such classes.

Finally, the convenience of these methods, in both C# and Python, comes with an associated risk. Using these techniques can make code more complex to understand and maintain.