Calcolare associazione e dissociazione

La biblioteca è tornata da te ancora una volta riguardo alla tua raccomandazione di promuovere Harry Potter usando Twilight. Temono che i due possano essere dissociati, il che potrebbe avere un impatto negativo sulla loro promozione. Ti chiedono di verificare che non sia così.

Ti viene subito in mente la metrica di Zhang, che misura in modo continuo associazione e dissociazione. L’associazione è positiva e la dissociazione è negativa. Come negli esercizi precedenti, il DataFrame books è già stato importato per te, insieme a numpy con l’alias np. La metrica di Zhang si calcola come segue:

$$Zhang(A \rightarrow B) = $$ $$\frac{Support(A \& B) - Support(A) Support(B)}{ max[Support(AB) (1-Support(A)), Support(A)(Support(B)-Support(AB))]}$$

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Analisi del carrello in Python

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Istruzioni dell'esercizio

Calcola il supporto di {Twilight} e il supporto di {Potter}.
Calcola il supporto di {Twilight, Potter}.
Completa l’espressione per il denominatore.
Calcola la metrica di Zhang per {Twilight} \(\rightarrow\) {Potter}.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# Compute the support of Twilight and Harry Potter
supportT = books['Twilight'].____
supportP = books['Potter'].____

# Compute the support of both books
supportTP = ____.mean()

# Complete the expressions for the numerator and denominator
numerator = supportTP - supportT*supportP
denominator = ___(supportTP*(1-supportT), supportT*(supportP-supportTP))

# Compute and print Zhang's metric
zhang = ____ / ____
print(zhang)

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Questo esercizio fa parte del corso

Analisi del carrello in Python

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In this chapter, you’ll learn the basics of Market Basket Analysis: association rules, metrics, and pruning. You’ll then apply these concepts to help a small grocery store improve its promotional and product placement efforts.

Exercise 1: What is market basket analysis?Exercise 2: The basics of market basket analysis Exercise 3: Cross-selling products Exercise 4: Identifying association rules Exercise 5: Multiple antecedents and consequents Exercise 6: Preparing data for market basket analysis Exercise 7: Generating association rules Exercise 8: The simplest metric Exercise 9: One-hot encoding transaction data Exercise 10: Computing the support metric

Association rules tell us that two or more items are related. Metrics allow us to quantify the usefulness of those relationships. In this chapter, you’ll apply six metrics to evaluate association rules: supply, confidence, lift, conviction, leverage, and Zhang's metric. You’ll then use association rules and metrics to assist a library and an e-book seller.

Exercise 1: Confidenza e lift Exercise 2: Consigliare libri con il supporto Exercise 3: Raffinare il supporto con la confidence Exercise 4: Ulteriore affinamento con il lift Exercise 5: Leverage e conviction Exercise 6: Lift vs leverage Exercise 7: Calcolare la conviction Exercise 8: Calcolare la conviction con una funzione Exercise 9: Promuovere ebook con conviction Exercise 10: Associazione e dissociazione Exercise 11: Calcolare associazione e dissociazione

Esercizio in corso

Exercise 12: Definire la metrica di Zhang Exercise 13: Applicare la metrica di Zhang Exercise 14: Regole avanzate Exercise 15: Filtrare con support e conviction Exercise 16: Usare il filtraggio multi-metrica per la promozione incrociata dei libri

The fundamental problem of Market Basket Analysis is determining how to translate vast amounts of customer decisions into a small number of useful rules. This process typically starts with the application of the Apriori algorithm and involves the use of additional strategies, such as pruning and aggregation. In this chapter, you’ll learn how to use these methods and will ultimately apply them in exercises where you assist a retailer in selecting a physical store layout and performing product cross-promotions.

Exercise 1: Aggregation Exercise 2: Performing aggregation Exercise 3: Defining an aggregation function Exercise 4: The Apriori algorithm Exercise 5: Pruning and Apriori Exercise 6: Identifying frequent itemsets with Apriori Exercise 7: Selecting a support threshold Exercise 8: Basic Apriori results pruning Exercise 9: Generating association rules Exercise 10: Pruning with lift Exercise 11: Pruning with confidence Exercise 12: Advanced Apriori results pruning Exercise 13: Aggregation and filtering Exercise 14: Applying Zhang's rule Exercise 15: Advanced filtering with multiple metrics

In this final chapter, you’ll learn how visualizations are used to guide the pruning process and summarize final results, which will typically take the form of itemsets or rules. You’ll master the three most useful visualizations -- heatmaps, scatterplots, and parallel coordinates plots – and will apply them to assist a movie streaming service.

Exercise 1: Heatmaps Exercise 2: Visualizing itemset support Exercise 3: Heatmaps with lift Exercise 4: Interpreting heatmaps Exercise 5: Scatterplots Exercise 6: Pruning with scatterplots Exercise 7: Optimality of the support-confidence border Exercise 8: Parallel coordinates plot Exercise 9: Using parallel coordinates to visualize rules Exercise 10: Refining a parallel coordinates plot Exercise 11: Congratulations!