Flash cards
Review the key moves
What is the main idea behind Go switch Statement?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ {Put the learning moves in the order that makes the concept easiest to apply.
The switch Statement
Use the switch statement to select one of many code blocks to be executed.
The switch statement in Go is similar to the ones in C, C++, Java, JavaScript, and PHP. The difference is that it only runs the matched case so it does not need a break statement.
Single-Case switch Syntax
Syntax
switch
expression {
case
x
// code block
case
y
// code block
case
z
...
default:
// code block
}This is how it works
- The expression is evaluated once
- The value of the switch expression is compared with the values of each case
- If there is a match, the associated block of code is executed
- The default keyword is optional. It specifies some code to run if there is no case match
Single-Case switch Example
The example below uses a weekday number to calculate the weekday name:
Example
package main
import ("fmt")
func main() {
day := 4
switch day {
case 1: fmt.Println("Monday")
case 2: fmt.Println("Tuesday")
case 3: fmt.Println("Wednesday")
case 4: fmt.Println("Thursday")
case 5: fmt.Println("Friday")
case 6: fmt.Println("Saturday")
case 7: fmt.Println("Sunday")
}
}The default Keyword
The default keyword specifies some code to run if there is no case match:
Example
package main
import ("fmt")
func main() {
day := 8
switch day {
case 1: fmt.Println("Monday")
case 2: fmt.Println("Tuesday")
case 3: fmt.Println("Wednesday")
case 4: fmt.Println("Thursday")
case 5: fmt.Println("Friday")
case 6: fmt.Println("Saturday")
case 7: fmt.Println("Sunday")
default: fmt.Println("Not a weekday")
}
}All the case values should have the same type as the switch expression. Otherwise, the compiler will raise an error:
Example
package main
import ("fmt")
func main() {
a := 3
switch a {
case 1: fmt.Println("a is one")
case "b": fmt.Println("a is b")
}
}