Re: [Matplotlib-users] animation.FuncAnimation example --- how does it work?

On 2015-04-23 03:22, Virgil Stokes wrote:
>
> 1. There are 3 positional arguments given for animation.FuncAnimation;
> but, in the
> API documentation for this class
> (http://matplotlib.org/api/animation_api.html), only
> two positional arguments are shown.

	One thing I think may be misleading you is that you seem to be 
misunderstanding how positional and keyword arguments work in Python. 
Specifying a default value for an argument in a function definition 
doesn't mean that you can *only* pass it by keyword when you call it. 
Any named argument can always be passed positionally or by keyword (in 
Python 2).  For instance, if I define a function like this:

def foo(a, b=2):
     print a+b

I can still call it like this:

foo(8, 10)

I can even call it like this (passing both arguments as keywords "out of 
order")

foo(b=10, a=8)

	Writing "b=2" in the function definition doesn't so much "make b a 
keyword argument" as just "specify a default value for b".  So in the 
FuncAnimation documentation you mentioned, "frames" is not required to 
be a keyword argument, and can still be passed positionally.  (In Python 
3 there are keyword-only arguments, and even in Python 2 the variadic 
**kwargs syntax collects only keyword arguments, but those aren't 
involved as far as the "frame" argument here is concerned.)

-- 
Brendan Barnwell
"Do not follow where the path may lead.  Go, instead, where there is no 
path, and leave a trail."
    --author unknown