Slices and Loops

Go has two data structures:

• Array is a fixed length list.
• Slice is an array that can grow or shrink. All elements inside the Slice needs to have the same data type.

Declare a Slice

cards := []string{}
// e.g.
cards := []string{newCard(), "Ten of Leafs", "Ace of Diamonds"}

Add Element to Slice

cards := []string{newCard(), "Ten of Leafs", "Ace of Diamonds"}
cards = append(cards, "Six of Spades")

Iterating over Slice Elements

cards := []string{newCard(), "Ten of Leafs", "Ace of Diamonds"}
for i, card := range cards {
  fmt.Println(i, card)
}

If we want to ignore the indices, we name them _:

for _, suit := range cardSuits {
  for _, value := range cardValues {
    cards = append(cards, value+" of "+suit)
  }
}

Slice Structure

When we declare a slice, Go initializes 2 data structures:

1. A new slice containing reference types:

• length (how many elements are in the array),
• capacity (how many elements are allowed in array)
• a pointer to the memory address of the first element of array.

2. An array with the elements and values

When we pass a slice as an argument into the function, Go:

1. Creates a copy of the slice into a different memory address.

2. The copied slice Pointer to the memory address of the first element of the array is the same as the original.