RandomizedSearch'e Hazırlık

Geçen dönem hocan, final sınavı notlarını tahmin etmek için bir kestirim modeli kurmanız konusunda sınıfına meydan okumuştu. Sen de hiperparametreleri rastgele seçerek birkaç farklı model çalıştırmayı denedin. Ancak her modeli çalıştırmak için tek tek kod yazman gerekiyordu.

RandomizedSearchCV() hakkında öğrendiklerinden sonra, en iyi modeli kurma hedefiyle hocanın meydan okumasına geri dönüyorsun. Bu egzersizde, rastgele aramayı tamamlamak için gereken üç girişi hazırlayacaksın.

Bu egzersiz

Python'da Model Doğrulama

kursunun bir parçasıdır

Kursu Görüntüle

Egzersiz talimatları

Parametre sözlüğünü, max_depth parametresi için 2, 4, 6 ve 8 seçeneklerini içeren bir liste ekleyerek tamamla.
On ağaçlı ve random_state değeri 1111 olan bir random forest regresyon modeli oluştur.
Kullanmak üzere bir mean squared error puanlayıcı (scorer) oluştur.

Uygulamalı interaktif egzersiz

Bu örnek kodu tamamlayarak bu egzersizi bitirin.

from sklearn.ensemble import RandomForestRegressor
from sklearn.metrics import make_scorer, mean_squared_error

# Finish the dictionary by adding the max_depth parameter
param_dist = {"____": [____],
              "max_features": [2, 4, 6, 8, 10],
              "min_samples_split": [2, 4, 8, 16]}

# Create a random forest regression model
rfr = ____(____=10, ____=1111)

# Create a scorer to use (use the mean squared error)
scorer = ____(____)

Kodu Düzenle ve Çalıştır

Bu egzersiz

Python'da Model Doğrulama

kursunun bir parçasıdır

IntermediárioNível de habilidade

4.9+

Kursa Ücretsiz Başlayın

Before we can validate models, we need an understanding of how to create and work with them. This chapter provides an introduction to running regression and classification models in scikit-learn. We will use this model building foundation throughout the remaining chapters.

Exercise 1: Introduction to model validation Exercise 2: Modeling steps Exercise 3: Seen vs. unseen data Exercise 4: Regression models Exercise 5: Set parameters and fit a model Exercise 6: Feature importances Exercise 7: Classification models Exercise 8: Classification predictions Exercise 9: Reusing model parameters Exercise 10: Random forest classifier

This chapter focuses on the basics of model validation. From splitting data into training, validation, and testing datasets, to creating an understanding of the bias-variance tradeoff, we build the foundation for the techniques of K-Fold and Leave-One-Out validation practiced in chapter three.

Exercise 1: Creating train, test, and validation datasets Exercise 2: Create one holdout set Exercise 3: Create two holdout sets Exercise 4: Why use holdout sets Exercise 5: Accuracy metrics: regression models Exercise 6: Mean absolute error Exercise 7: Mean squared error Exercise 8: Performance on data subsets Exercise 9: Classification metrics Exercise 10: Confusion matrices Exercise 11: Confusion matrices, again Exercise 12: Precision vs. recall Exercise 13: The bias-variance tradeoff Exercise 14: Error due to under/over-fitting Exercise 15: Am I underfitting?

Holdout sets are a great start to model validation. However, using a single train and test set if often not enough. Cross-validation is considered the gold standard when it comes to validating model performance and is almost always used when tuning model hyper-parameters. This chapter focuses on performing cross-validation to validate model performance.

Exercise 1: The problems with holdout sets Exercise 2: Two samples Exercise 3: Potential problems Exercise 4: Cross-validation Exercise 5: scikit-learn's KFold()Exercise 6: Using KFold indices Exercise 7: sklearn's cross_val_score()Exercise 8: scikit-learn's methods Exercise 9: Implement cross_val_score()Exercise 10: Leave-one-out-cross-validation (LOOCV)Exercise 11: When to use LOOCV Exercise 12: Leave-one-out-cross-validation

The first three chapters focused on model validation techniques. In chapter 4 we apply these techniques, specifically cross-validation, while learning about hyperparameter tuning. After all, model validation makes tuning possible and helps us select the overall best model.

Exercise 1: Hiperparametre ayarına giriş Exercise 2: Hiperparametreler Oluşturma Exercise 3: Aralıklar kullanarak bir modeli çalıştırma Exercise 4: RandomizedSearchCV Exercise 5: RandomizedSearch'e Hazırlık

Geçerli Egzersiz

Exercise 6: RandomizedSearchCV Uygulama Exercise 7: Nihai modelini seçme Exercise 8: En iyi sınıflandırma doğruluğu Exercise 9: En iyi precision modelini seçmek Exercise 10: Kurs tamamlandı!