Power with modulu

[Fredrik Lundh]

Roie Kerstein wrote:

> I want to compute a**b%c for very long numbers.
> Computing a**b and then applying modulu is not practical, since it takes
> ages.
> There is a built-in optional parameter to the long.__pow__(a,b[,modulu]),
> and it works well.
> My question is: How can I write it is a form of an expression, like a**b?

if you look up __pow__ in the documentation, you'll find that it explains
that __pow__ is used to implement the built-in pow() function:

    http://docs.python.org/lib/built-in-funcs.html#l2h-54

in other words,

    pow(a, b, c)

does what you want.

</F>