Python array multiply

Question

hh=[[82.5], [168.5]]
N=1./5
ll=N*hh

I am getting an error while running this:

"can't multiply sequence by non-int of type 'float'"

I tried to add float(), but this does not solve my problem. How can I fix this?

Answer 1

When you multiply a sequence by X in Python, it doesn't multiply each member of the sequence - what it does is to repeat the sequence X times. That's why X has to be an integer (it can't be a float).

What you want to do is to use a list comprehension:

hh = [[82.5], [168.5]]
N  = 1.0 / 5
ll = [[x*N for x in y] for y in hh]