k-Nearest Neighbors: Fitten

In deze oefening bouw je je eerste classificatiemodel met de gegevensset churn_df, die voor de rest van het hoofdstuk al is ingeladen.

De target, "churn", moet één kolom zijn met evenveel observaties als de featuredata. De featuredata is al omgezet naar numpy-arrays.

"account_length" en "customer_service_calls" worden als features gebruikt, omdat de duur van het abonnement iets zegt over klantloyaliteit, en veel contact met de klantenservice op ontevredenheid kan wijzen — beide zijn goede voorspellers van churn.

Deze oefening maakt deel uit van de cursus

Supervised Learning met scikit-learn

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Oefeninstructies

Importeer KNeighborsClassifier uit sklearn.neighbors.
Instantieer een KNeighborsClassifier met 6 buren en noem deze knn.
Fit de classifier op de data met de methode .fit().

Praktische interactieve oefening

Probeer deze oefening eens door deze voorbeeldcode in te vullen.

# Import KNeighborsClassifier
from ____.____ import ____ 

y = churn_df["churn"].values
X = churn_df[["account_length", "customer_service_calls"]].values

# Create a KNN classifier with 6 neighbors
knn = ____(____=____)

# Fit the classifier to the data
knn.____(____, ____)

Code bewerken en uitvoeren

Deze oefening maakt deel uit van de cursus

Supervised Learning met scikit-learn

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In this chapter, you'll be introduced to classification problems and learn how to solve them using supervised learning techniques. You'll learn how to split data into training and test sets, fit a model, make predictions, and evaluate accuracy. You’ll discover the relationship between model complexity and performance, applying what you learn to a churn dataset, where you will classify the churn status of a telecom company's customers.

Exercise 1: Machine Learning met scikit-learn Exercise 2: Binaire classificatie Exercise 3: De supervised learning-workflow Exercise 4: De classificatie-uitdaging Exercise 5: k-Nearest Neighbors: Fitten

Huidige oefening

Exercise 6: k-Nearest Neighbors: voorspellen Exercise 7: Modelprestaties meten Exercise 8: Train/test-split + nauwkeurigheid berekenen Exercise 9: Overfitting en underfitting Exercise 10: Modelcomplexiteit visualiseren

In this chapter, you will be introduced to regression, and build models to predict sales values using a dataset on advertising expenditure. You will learn about the mechanics of linear regression and common performance metrics such as R-squared and root mean squared error. You will perform k-fold cross-validation, and apply regularization to regression models to reduce the risk of overfitting.

Exercise 1: Introduction to regression Exercise 2: Creating features Exercise 3: Building a linear regression model Exercise 4: Visualizing a linear regression model Exercise 5: The basics of linear regression Exercise 6: Fit and predict for regression Exercise 7: Regression performance Exercise 8: Cross-validation Exercise 9: Cross-validation for R-squared Exercise 10: Analyzing cross-validation metrics Exercise 11: Regularized regression Exercise 12: Regularized regression: Ridge Exercise 13: Lasso regression for feature importance

Having trained models, now you will learn how to evaluate them. In this chapter, you will be introduced to several metrics along with a visualization technique for analyzing classification model performance using scikit-learn. You will also learn how to optimize classification and regression models through the use of hyperparameter tuning.

Exercise 1: How good is your model?Exercise 2: Deciding on a primary metric Exercise 3: Assessing a diabetes prediction classifier Exercise 4: Logistic regression and the ROC curve Exercise 5: Building a logistic regression model Exercise 6: The ROC curve Exercise 7: ROC AUC Exercise 8: Hyperparameter tuning Exercise 9: Hyperparameter tuning with GridSearchCV Exercise 10: Hyperparameter tuning with RandomizedSearchCV

Learn how to impute missing values, convert categorical data to numeric values, scale data, evaluate multiple supervised learning models simultaneously, and build pipelines to streamline your workflow!

Exercise 1: Preprocessing data Exercise 2: Creating dummy variables Exercise 3: Regression with categorical features Exercise 4: Handling missing data Exercise 5: Dropping missing data Exercise 6: Pipeline for song genre prediction: I Exercise 7: Pipeline for song genre prediction: II Exercise 8: Centering and scaling Exercise 9: Centering and scaling for regression Exercise 10: Centering and scaling for classification Exercise 11: Evaluating multiple models Exercise 12: Visualizing regression model performance Exercise 13: Predicting on the test set Exercise 14: Visualizing classification model performance Exercise 15: Pipeline for predicting song popularity Exercise 16: Congratulations