Go Arrays, Slices and Maps

An array has a fixed length. A slice is a flexible view of an array and is what you normally use. A map stores key-value pairs.

ExampleGo

package main

import (
  "fmt"
  "sort"
)

func main() {
  arr := [3]int{10, 20, 30}
  fmt.Println(arr, len(arr))

  nums := []int{5, 2, 9}
  nums = append(nums, 1)
  sort.Ints(nums)
  fmt.Println(nums, len(nums), nums[1:3])

  ages := map[string]int{"Ada": 36, "Sam": 22}
  ages["Lee"] = 41
  delete(ages, "Sam")
  fmt.Println(ages, len(ages))
  v, ok := ages["Nobody"]
  fmt.Println(v, ok)
}

Output

[10 20 30] 3
[1 2 5 9] 4 [2 5]
map[Ada:36 Lee:41] 2
0 false

A lookup in a map can return two values: the value, and an ok flag telling you whether the key was really there.

Quick check

What does append do?

Adds items to a slice and returns the new sliceJoins two stringsRemoves the last item

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

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