I'm trying to update a multiplicative value to a variable.
I know that I can do += and -= for addition and subtraction and *= for multiplication, but I don't fully grasp the entirety of that type of operation. Can someone point me to the documentation that covers this? I can't seem to find it on python.org.
Well technically you are never updating python variables (integers, strings and floats among many other are immutable), you are re-assigning a value to a name.
+ is shorthand for add(), * is shorthand for mul() and - is short for sub().
since you are re-assigning variable, you are essentially performing these operations (when adding, substracting, multiplying, dividing or whatever it is that you do):
a = 1
a = a + 1 # a = 2
a = a * 2 # a = 4
a = a - 1 # a = 3
+=, -= and *= are just shorts for the above expressions.
i.e. the above can be restated as:
a = 1
a += 1
a *= 2
a -= 1
python docs for operators: https://docs.python.org/3.5/library/operator.html see also python docs for inplace operators for more information: https://docs.python.org/3.5/library/operator.html#inplace-operators
