Cannot convert string to float

Question

I am getting information from a csv, I need to take a field which in theory is a float, but can come empty, I'm this function which takes the row [i] where the float is, and should return the float,

def fun(x):
    if not(x):
        x=0
        x=float(x)
    else:
        x = float(x)
    return x

but when i try it throws me this error tells me "float () argument must be a string or a number"

Answer 1

Ok, how about

def fn(x):
    try:
        return float(x)
    except (ValueError, TypeError):
        return 0.0