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iOS Swift 2.0 Collections and Control Flow Introduction to Collections Working with Arrays

Swift

Challenge Task 2 of 4

Now that we have an array declared, since it is a mutable array, we can add and remove items. Let's start by adding two more values to our existing array. There are two ways we can add items to an array and I want you to give both a try. Add one item to the array using the append method.

Remember: We invoke methods on an array using a period or dot. After the dot we write out the method name and a value to append in parentheses following the name.

Add another item to the array by concatenating an array. When concatenating, assign the results of the expression back to arrayOfInts.

arrays.swift
// Enter your code below

var arrayOfInts = [1,2,3,4,5,6,7]

var arrayOfInts.append("8")

1 Answer

Brendan Whiting
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Brendan Whiting
Front End Web Development Techdegree Graduate 84,735 Points

1) you shouldn't use 'var' when you use the append method. You only use 'var' when you declare the variable the first time. Every other time, you're just calling the variable, not declaring it, and you leave out the var

2) Because you put the "8" in quotes, it is a String. But arrays need to be all of the same type (in Swift, not all languages), and arrayOfInts is already set up with Ints. So you need to take the quotes off for this to be appended.

3) They're also asking for you to add an item to your array a 2nd way in addition to the append method - using the concatenation method. The syntax for that is using the += and the square brackets. For example: arrayOfInts += [9]