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Switch Statements

2:25 with Jay McGavren

To choose between several options with "if" / "else" statements, you'd have to nest them several deep, which is hard to read. So like most programming languages, Go offers a "switch" statement. You specify the expression you want to switch on, "case" statements with possible values for that expression, and one or more lines of code that should run in each case.

  • To choose between several options with if / else statements, you'd have to nest them several deep, which is hard to read
  • So like most programming languages, Go offers a switch statement.
  • You specify the expression you want to switch on, case statements with possible values for that expression, and one or more lines of code that should run in each case.
  • You can add a default case at the end, that will run if none of the other cases match.
package main

import (
    "fmt"
)

func main() {
    fmt.Print("You win: ")
    doorNumber := 2
    switch doorNumber {
    case 1:
        fmt.Println("a new car!") // not printed
    case 2:
        fmt.Println("a llama!") // printed
    default:
        fmt.Println("a goat!") // not printed
    }
}

To choose between several different options, using if and 0:00
else states, you'd have to nest some several deep, which can be hard to read. 0:03
So like most programming languages, Go offers a switch statement. 0:07
You specify the expression you wanna switch on, case statements with 0:11
possible values for that expression, and then code that should run for each case. 0:14
You can also add the default case at the end, 0:20
that will run if none of the other cases match. 0:22
So up here, we've initialized the doorNumber variable with the value 2, 0:25
the integer 2. 0:30
And we're going to switch on the value that's in doorNumber. 0:32
So we've got case statements here, for possible values of doorNumber. 0:35
If doorNumber was set to 1, we would print the string, a new car! 0:38
But up here, it's actually set to 2, so 0:44
it's going to match this case here, case number 2. 0:47
And it means that his code here will run, it will print the string, a llama! 0:51
So if we try running this down here, we'll see, You win a llama! 0:57
Let's try going up here into the code and setting it to 1, so 1:01
that we can look at the other case. 1:04
Try running this again. 1:07
This time, you can see we won a new car. 1:08
And if we set it to some completely different value, 1:10
let's say we pick door number 99. 1:14
In that case none of the cases here will match, and 1:16
therefore the default case will run instead. 1:20
And it will print, You win a goat! 1:24
Let's change this back to doorNumber 1, up here. 1:27
In some languages, the case after the selected case will also run, 1:31
unless you insert a break statement at the end of the case. 1:34
In Go, only the selected case runs by default. 1:37
So, if we select doorNumber 1, only doorNumber 1 runs. 1:40
But you can run the next case as well, 1:43
if you explicitly include the fallthrough keyword. 1:46
So lets type fallthrough here, and try re-running it. 1:51
And now, we win both a new car and a llama. 1:55
That ends our tour of control structures in Go. 1:58
Go's a very simple language, so 2:01
you've actually learned a substantial part of its syntax already. 2:03
The next stage is going to be a bit longer than this one. 2:08
We're going to look at the different ways Go can store data, and 2:10
there are a lot of them. 2:13
We'll learn about slices, maps, structs and more. 2:15
Learning them will take a bit of work, but 2:18
when you're done, you'll have a variety of ways to simplify your programs. 2:19
See in the next stage. 2:23

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