Kaggle - Intermediate ML - Compare models, create a CSV

# **********************************************************************************
# **********************************************************************************
# 0. Function for comparing different models
# **********************************************************************************
# **********************************************************************************

def score_model(model, X_t=X_train, X_v=X_valid, y_t=y_train, y_v=y_valid):
    model.fit(X_t, y_t)
    preds = model.predict(X_v)
    return mean_absolute_error(y_v, preds)



# **********************************************************************************
# **********************************************************************************
# 1. Split the dataset
# **********************************************************************************
# **********************************************************************************

import pandas as pd
from sklearn.model_selection import train_test_split

# Read the data
X_full = pd.read_csv('../input/train.csv', index_col='Id')
X_test_full = pd.read_csv('../input/test.csv', index_col='Id')

# Obtain target and predictors
y = X_full.SalePrice
features = ['LotArea', 'YearBuilt', '1stFlrSF', '2ndFlrSF', 'FullBath', 'BedroomAbvGr', 'TotRmsAbvGrd']
X = X_full[features].copy()
X_test = X_test_full[features].copy()

# Break off validation set from training data
X_train, X_valid, y_train, y_valid = train_test_split(X, y, train_size=0.8, test_size=0.2, random_state=0)



# **********************************************************************************
# **********************************************************************************
# 2. Create 5 models of RandomForestRegressor
# **********************************************************************************
# **********************************************************************************

from sklearn.ensemble import RandomForestRegressor

# Define the models
model_1 = RandomForestRegressor(n_estimators=50, random_state=0)
model_2 = RandomForestRegressor(n_estimators=100, random_state=0)
model_3 = RandomForestRegressor(n_estimators=100, criterion='absolute_error', random_state=0)
model_4 = RandomForestRegressor(n_estimators=200, min_samples_split=20, random_state=0)
model_5 = RandomForestRegressor(n_estimators=100, max_depth=7, random_state=0)

models = [model_1, model_2, model_3, model_4, model_5]



# **********************************************************************************
# **********************************************************************************
# 3. Print the score of its model
# **********************************************************************************
# **********************************************************************************

from sklearn.metrics import mean_absolute_error

for i in range(0, len(models)):
    mae = score_model(models[i])
    print("Model %d MAE: %d" % (i+1, mae))
best_model = model_3


# **********************************************************************************
# **********************************************************************************
# 4. Create a new model
# **********************************************************************************
# **********************************************************************************

my_model = RandomForestRegressor()
my_model.fit(X, y)
preds_test = my_model.predict(X_test)

# Save predictions in format used for competition scoring
output = pd.DataFrame({'Id': X_test.index,'SalePrice': preds_test})
output.to_csv('submission.csv', index=False)