Python 利用字典计算数据中不重复的数量

datas = "x1 x2 x2 x3 x4 x5 x6 x7 x7 x8 x9"
for data in datas.split():
print(data)

dict = {data: None for data in datas.split()}#data为键，None为键对应的值（任意值）
print("dict=",dict)
print("不重复的长度：",len(dict))

x1
x2
x2
x3
x4
x5
x6
x7
x7
x8
x9
dict= {'x1': None, 'x7': None, 'x4': None, 'x9': None, 'x6': None, 'x2': None, 'x5': None, 'x8': None, 'x3': None}
不重复的长度： 9