X_train, X_test, X_val, y_train, y_test, y_val for regression model with Keras or tensorflow?

How could I randomly split a data matrix and the corresponding label vector into a X_train, X_test, X_val, y_train, y_test, y_val for regression model with Keras or tensorflow..???

I have also added a picture where the data was splitter in three different classes. in each column the value of R (Coefficient of determination) is given. Please also let me know about how can i calculate this value of R in Keras/Tensor flow.

Please help me in this regard.