Need to use range with decimals

[KameronG]

Ok,so now I have this:

if ran == "range":
    i = float(input("What is the minimum z value?"))
    k = float(input("What is the maximum z value?"))
    u = float(input("By what increment?"))
    data = []
    current = i
    while i < k:
        data.append(i)
        current += u

But after asking for the min, max and increment, nothing happens. I'm guessing I need something in the brackets after data, but I'm not sure what would go there.