Ancora su vapply()

La differenza tra vapply() e sapply() è stata mostrata nell'ultimo esempio per evidenziare come vapply() fallisca correttamente, ma cosa succede quando non fallisce? Quando non ci sono errori, vapply() restituisce un risultato semplificato in base all'argomento FUN.VALUE.

Il dataset stock_return con i rendimenti giornalieri di Apple, IBM e Microsoft è già disponibile. Anche la funzione sharpe() è a tua disposizione.

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Istruzioni dell'esercizio

Calcola lo Sharpe ratio per ciascun titolo usando vapply().
Usa summary() sulla colonna apple per ottenere il riepilogo a 6 numeri.
Applica vapply() con la funzione summary() a stock_return per riassumere ogni colonna.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# Sharpe ratio for all stocks
vapply(___, ___, FUN.VALUE = numeric(___))

# Summarize Apple
___

# Summarize all stocks
vapply(___, ___, FUN.VALUE = numeric(___))

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Esercizio in corso

Exercise 11: Funzioni anonime Exercise 12: Complimenti