train_test_split.py

def time_series_train_test_split(time_series, train_split_fraction):
    """
    Split the data into training and test set.
    """
    split_index = int(round(time_series.shape[0]*train_split_fraction, 0))
    train_set = time_series[:split_index]
    test_set = time_series[:-split_index]
    return train_set, test_set

### EXECUTE IN MAIN FUNCTION ###
training_set, test_set = time_series_train_test_split(time_series = df['Geothermal_net_generation'], 
                                                      train_split_fraction = .75)