我不断收到错误名称'y_test'未定义

Question

I really need your help: I've written this code:

from sklearn.model_selection import train_test_split
from sklearn import metrics
from sklearn.metrics import accuracy_score

def train_test_rmse(x,y):
    X = df_new[feature_cols]
    y = df_new['TOTAL CONSTRUCTION COST - EXCLUDING TAX']
    X_train, X_test, y_train, y_test = train_test_split(x, y, test_size = 0.2,random_state=123)
    linreg = LinearRegression()
    linreg.fit(X_train, y_train)
    y_test = train_test_split(x, y, test_size = 0.2,random_state=123)
    y_pred = linreg.predict(X_test)
    print(accuracy_score(y_test, y_pred))  
    return np.sqrt(metrics.mean_squared_error(y_test, y_pred)) 

^ The code above runs correctly. But when I try to plot a scatter plot in the cell beneath:

import matplotlib.pyplot as plt
plt.scatter(y_test, y_pred)
plt.xlabel('Actual Y')
plt.ylabel('Predicted Y')
plt.show()

I get the error "name 'y_test' is not defined". Please let me know how to fix it. Thanks.

Answer 1

In the code, i see that y_test is defined inside the train_test_rmse function, you need to initialize y_test outside this function.

your code should work fine with few changes as follows:

y_test = None

def train_test_rmse(x,y):
  
  global y_test
  
    X = df_new[feature_cols]
    y = df_new['TOTAL CONSTRUCTION COST - EXCLUDING TAX']
    X_train, X_test, y_train, y_test = train_test_split(x, y, test_size = 0.2,random_state=123)