此代码用于我在ML在线课程中学习的数据预处理。

import numpy as np
import matplotlib.pyplot as plt  #pyplot is a sublibrary of matplotlib
import pandas as pd

dataset = pd.read_csv('Data.csv')
X = dataset.iloc[:,:-1]
Y = dataset.iloc[:,-1]


from sklearn.impute import SimpleImputer
imputer = SimpleImputer(missing_values = np.nan,strategy = 'mean',verbose = 0) 
imputer = imputer.fit(X[:,1:3])
X[:,1:3] = imputer.transform(X[:,1:3])

但是它给出了这个Type错误：无法散列的类型：'sl​​ice'。 请帮助我。