How to round each item in a list of floats to 2 decimal places?

"%.2f" does not return a clean float. It returns a string representing this float with two decimals.

my_list = [0.30000000000000004, 0.5, 0.20000000000000001]
my_formatted_list = [ '%.2f' % elem for elem in my_list ]

returns:

['0.30', '0.50', '0.20']

Also, don't call your variable list. This is a reserved word for list creation. Use some other name, for example my_list.

If you want to obtain [0.30, 0.5, 0.20] (or at least the floats that are the closest possible), you can try this:

my_rounded_list = [ round(elem, 2) for elem in my_list ]

returns:

[0.29999999999999999, 0.5, 0.20000000000000001]