“float”和“str”实例之间不支持Python类型错误“

我一直在关注这个教程系列，其中讲师没有错误，但我有，在最后一行，错误表示类型错误修复了我的问题。csv文件中的数据已更改，因此导致了错误

import numpy as np
import matplotlib.pyplot as plt
import pandas as pd

#Import Data set

dataset= pd.read_csv('Data.csv') 
X = dataset.iloc[:,:-1].values
Y = dataset.iloc[:,3].values

#X[:,1:3].astype(str)

#Taking Care of The Missing Data
from sklearn.preprocessing import Imputer

imputer = Imputer(missing_values=np.nan,strategy='mean',axis=0)
imputer = imputer.fit(X[:,1:3])

X[:,1:3] = imputer.transform(X[:,1:3])

#Taking care of Categorical data
from sklearn.preprocessing import LabelEncoder, OneHotEncoder
labelencoder_X = LabelEncoder()
X[:,0]= labelencoder_X.fit_transform(X[:,0])

#OneHot for Dummy Variables
onehotencoder= OneHotEncoder(categorical_features=[0])
X= onehotencoder.fit_transform(X).toarray()


labelencoder_Y = LabelEncoder()
Y= labelencoder_X.fit_transform(Y)

#Split data into Train and test
from sklearn.cross_validation import train_test_split
X_train, X_test, Y_train, Y_test = train_test_split(X, Y, test_size=0.2, 
random_state=0)