Tutti insieme, adesso!

Ottimo! Hai imparato molto su operatori e sottoinsiemi. Questo ti tornerà utile nei futuri progetti di analisi dei dati. Facciamo un ultimo esercizio che combina diversi operatori.

È disponibile una nuova versione del data frame stocks da usare.

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Istruzioni dell'esercizio

Per prima cosa, stampa stocks. Contiene i prezzi di Apple e Microsoft per dicembre 2016.
Sembra che ci siano dati mancanti. Indaghiamo meglio. Usa weekdays() sulla colonna date e assegnane il risultato a stocks come nuova colonna weekday.
Visualizza ora stocks. I dati mancanti sono nei weekend! Ha senso: il mercato azionario è chiuso nei fine settimana.
Rimuovi le righe con valori mancanti usando subset(). Usa !is.na() su apple come condizione. Assegna questo nuovo data frame a stocks_no_NA.
Ora ti interessano i giorni in cui apple era sopra 117, oppure quando micr era sopra 63. Usa operatori relazionali, | e subset() per farlo con stocks_no_NA.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# View stocks
___

# Weekday investigation
stocks$weekday <- 

# View stocks again
___

# Remove missing data
stocks_no_NA <- ___

# Apple and Microsoft joint range
___

Modifica ed esegui il codice

Questo esercizio fa parte del corso

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Esercizio in corso

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