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Sourabh Pal
210 PointscardsInPile in forEachIndexed function
How the line val cardsInPile: MutableList<Card> = Array(i+1, {deck.drawCard()}).toMutableList()
draws cards from deck more than once? I think the for each loop iterates over each tableauPile index i.e. 7 times. But when it creates the cardsInPile for each iteration how come each array item withdraws a card from the deck?
2 Answers
andren
28,558 PointsThe lambda you pass as a second argument to the Array constructor is used to generate the default value of the items in the array.
That means that if you have this code for example:
CardsInPile: MutableList<Card> = Array(5, {deck.drawCard()}).toMutableList()
Kotlin would call deck.drawCard() once to set the value of the first element, then again to set the value of the second element, then again to set the value of the third element, and so on. Until all of the elements had a default value.
So the above code would call deck.drawCard() 5 times, since there are 5 elements in the array.
Maybe this example from the official kotlin docs clarifies how it works a bit better:
// Creates an Array<String> with values ["0", "1", "4", "9", "16"]
val asc = Array(5, { i -> (i * i).toString() })
Sourabh Pal
210 PointsThank you for you answer. Now i totally understand how it works. It just skipped out of my mind that its a lambda expression