And / Or

Potresti voler verificare più condizioni relazionali contemporaneamente. E se volessi sapere se il titolo Apple è sopra 120 ma sotto 121? I semplici operatori relazionali non bastano! Per più condizioni, ti servono l'operatore And & e l'operatore Or |.

& (And): un'intersezione. a & b è TRUE solo se sia a che b sono TRUE.
| (Or): un'unione. a | b è TRUE se almeno uno tra a e b è TRUE.

apple <- c(120.00, 120.08, 119.97, 121.88)

# Devono valere entrambe le condizioni
(apple > 120) & (apple < 121)
[1] FALSE  TRUE FALSE FALSE

# Deve valere almeno una condizione
(apple <= 120) | (apple > 121)
[1]  TRUE FALSE  TRUE  TRUE

Il data frame stocks è a tua disposizione.

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Istruzioni dell'esercizio

Quando ibm è compreso tra 171 e 176? Aggiungi il vettore logico a stocks come ibm_buy_range.
Controlla se panera scende sotto 213.20 oppure sale sopra 216.50, poi aggiungilo a stocks come colonna panera_spike.
Supponi che ti interessino le date successive a 2017-01-21 ma precedenti a 2017-01-25, in modo esclusivo. Usa as.Date() e & per questo. Aggiungi il risultato a stocks come good_dates.
Stampa stocks.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# IBM buy range	
___

# Panera spikes	
___

# Date range
___

# Print stocks	
___

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