Removing Cards

We've only got one function standing between us and a finished Tableau class 0:00 and that's the remove cards function, but it won't be left standing for long. 0:04 Let's start by declaring our remove cards function right after our add cards 0:08 function. 0:13 Fun, remove cards, then for the parameter let's add an integer 0:13 named tapped index to represent which card was tapped. 0:19 And then add our brackets. 0:29 Now, we just need to remove the cards from our cards list from 0:30 the tappedIndex to the end. 0:34 To do that, we're going to use a for loop. 0:36 And Kotlin for loops are a little bit different than in Java. 0:39 For starters, in Kotlin all for loops take the form of some variable 0:43 followed by the in keyword and then the thing you'd like to loop over. 0:48 So if we wanted to loop over all the cards in our cards list, we would just type for 0:52 card in cards and then add our brackets. 0:58 Notice that I didn't use a var or vow to declare the card variable and 1:03 a for loop it's always going to be immutable. 1:08 So we can leave that part off. 1:11 So that's nice but we don't really want to loop through our entire card's list. 1:13 We just want to loop from the tappedIndex to the end. 1:17 So instead of looping with a card let's loop with an index like we're used to. 1:20 And let's use i and instead of having the cards list as the thing we'd like to loop 1:25 over, let's just use a range from the tappedIndex to the end. 1:30 A range is just a set of numbers like the numbers between one and seven. 1:35 If we wanted to print the numbers one through seven, 1:41 we could use a range like this one. 1:43 The two dots represent that this range 1:46 will include all the integers between one and seven. 1:48 But these dots only work if the range is increasing. 1:52 If we want to go from seven down to one we would need to write 7 downTo 1. 1:55 Now that we've got that covered, 2:02 let's loop over a range from the tappedIndex to the lastIndex. 2:04 Let's delete 7 downTo 1 and instead write tappedIndex to 2:09 cards.lastIndex. 2:14 And now we're successfully looping from the tappedIndex to the lastIndex. 2:19 So to remove those cards let's jump and set our four loop and 2:24 remove the card index i. 2:28 cards.removeAt and pass in i. 2:29 Finally, now that we've handled removing the cards, 2:36 we just need to make sure that the last card in our pile is face up, 2:39 provided that there is a last card in our pile. 2:43 Below our for 2:46 loop let's first make sure there's at least one card in our cards list. 2:47 If cards.size is greater than 2:51 zero and if there are let's set the last card to face up, 2:56 cards.last.faceUp equals true. 3:01 All right, we're all finished with our tableau class. 3:09 All that's left is to jump over to our game model class and 3:13 create a property for our tableau piles. 3:17 Let's add a line below our foundation piles and then type val tableau piles 3:20 and let's set it equal to a new array of size seven. 3:27 And then let's populate our array with seven instances of an empty tableau pile. 3:34 Remember, we'll be creating the tableau piles at the start of every game. 3:39 So for now we're just populating them with something so we don't get an error. 3:43 To populate our seven tableau piles, 3:47 let's use a lambda expression like we did in our debt class. 3:49 Let's start with the brackets, and then inside let's create a new tableau pile. 3:53 And since each tableau pile needs to be created with a list of cards, 4:01 let's add mutable list of as our parameter to initialize it with an empty list. 4:05 Next let's flip back to our Tableau pile class and inside the init 4:11 block let's copy in this if card.size greater than zero section. 4:16 To make sure we don't try to access a last card that doesn't exist. 4:27 After all, we did just call the constructor with an empty list. 4:32 So at this point, it's guaranteed to happen. 4:36 For one final step, I think it looks a little bit cleaner 4:39 if we just have an empty list be the default value for our cards list. 4:42 So inside our constructor let's add equals mutable list of and 4:46 now that we've got a default value. 4:52 Let's jump back to our game model and 4:54 now we can get rid of this unnecessary parameter. 4:57 We've come so far since the beginning of this course. 5:02 We've learned tons about Kotlin and we just finished up our Tableau object 5:05 which was the last object we needed to start modeling our game of solitaire. 5:09 But before we can move on, I feel like we've been doing a lot of coding and 5:14 we haven't been able to check if any of that works. 5:18 So let's take a minute and write some tests for a tableau pile. 5:21