str转换为float浮点数后，结果展示问题
程序代码：CHAR_TO_FLOAT = {
'0': 0,
'1': 1,
'2': 2,
'3': 3,
'4': 4,
'5': 5,
'6': 6,
'7': 7,
'8': 8,
'9': 9,
'.': -1
}
def str2float1(s):
nums = map(lambda ch: CHAR_TO_FLOAT[ch], s)
point = 0
def to_float(f, n):
nonlocal point
if n == -1:
point = 1
return f
if point == 0:
return f * 10 + n
else:
point = point * 10
return f + n / point
return reduce(to_float, nums, 0.0)用：print(str2float1('120.123'))打印时，结果为：120.12299999999999能解释下不?
