Q:

Python if(a & ! b): syntax? 

What's the syntax for: 
 if(a & ! b): 

I've been using javascript for a while and just can't seem to recall how you specify ! b

A:

The straight translation (bitwise and and logical not) would be:
if a & not b:

As in JavaScript, this always evaluates both operands and performs a bitwise and operation; for example, if b is 0 and a is 2 the result will be 0 (2 & 1 == 0). 
However, most probably, you meant logical and and logical not, as in
if(a && ! b)

In Python, that would be:
if a and not b:

In this case, if b is 0 and a is 2 you'll get True (2 and not 0 -> 2 and True -> True). 
As for && in JavaScript, Python's and performs short-circuit evaluation, so if the left hand is False it won't evaluate the right-hand side, and if the left-hand-side is truthy, the right-hand-side is returned as-is (not converted to bool).