Golang function switch statement application skills

As Golang continues to develop rapidly in recent years, it has become one of the preferred programming languages ​​​​for many developers. Among Golang's many grammatical structures, the switch statement is undoubtedly a very important part. However, many developers may only use the simplest switch statement, but do not know much about the further application skills of the switch statement. This article will introduce some common application techniques of switch statements in Golang functions, in order to help readers better understand and apply switch statements.

1. No expression required

In a general switch statement, we will provide an expression, so that the program can determine which case to execute based on the value of the expression statement. However, in Golang, we can use a switch statement without an expression to let the program jump to the first case statement that satisfies the condition. The following is an example:

package main

import "fmt"

func main() {
    i := 3
    switch {
    case i < 3:
        fmt.Println("i is less than 3")
    case i == 3:
        fmt.Println("i is equal to 3")
    case i > 3:
        fmt.Println("i is greater than 3")
    }
}

According to the value of i, the program will output "i is equal to 3". This feature is very useful when you need to evaluate multiple conditions in sequence, but don't want to use multiple if statements.

2. You can use multiple expressions

In a general switch statement, we can only use one expression. However, in Golang, we can use multiple expressions separated by commas. The following is an example:

package main

import "fmt"

func main() {
    i, j := 3, 4
    switch i, j {
    case 1, 2:
        fmt.Println("i is either 1 or 2")
    case 3, 4:
        fmt.Println("i is either 3 or 4")
    }
}

According to the values ​​​​of i and j, the program will output "i is either 3 or 4". This feature is very useful when multiple conditions need to be judged, but each condition is not mutually exclusive.

3. You can use type assertions

In Golang, we can use type assertions to determine the type of a value. Therefore, in the switch statement, we can also use type assertions to perform type judgment. The following is an example:

package main

import "fmt"

func main() {
    var i interface{} = 1
    switch i.(type) {
    case int:
        fmt.Println("i is an int")
    case float64:
        fmt.Println("i is a float64")
    case string:
        fmt.Println("i is a string")
    }
}

The program will output "i is an int". This feature is very useful when you need to judge different types of values.

4. You can use the fallthrough keyword

In Golang, we can use the fallthrough keyword to let the program execute the next case statement without conditional judgment. The following is an example:

package main

import "fmt"

func main() {
    i := 1
    switch i {
    case 1:
        fmt.Println("i is 1")
        fallthrough
    case 2:
        fmt.Println("i is 2")
    }
}

The program will output "i is 1" and "i is 2". This feature is very useful when multiple case statements need to be executed.

5. You can use the default statement

In a general switch statement, if none of the conditions of a case statement is met, the program will exit the switch statement. However, in Golang, we can use default statement in switch statement to handle such situations. The following is an example:

package main

import "fmt"

func main() {
    i := 5
    switch i {
    case 1:
        fmt.Println("i is 1")
    case 2:
        fmt.Println("i is 2")
    default:
        fmt.Println("i is neither 1 nor 2")
    }
}

The program will output "i is neither 1 nor 2". This feature is very useful when a type of situation needs to be processed but there is no specific conditional judgment.

6. You can use the switch statement as a function return value

In Golang, the switch statement can be used as a function return value. This feature is very useful because it makes programs more concise and readable. The following is an example:

package main

import "fmt"

func main() {
    i, j := 1, 2
    switch {
    case i < j:
        fmt.Printf("%d is less than %d
", i, j)
    case i == j:
        fmt.Printf("%d is equal to %d
", i, j)
    case i > j:
        fmt.Printf("%d is greater than %d
", i, j)
    }
}

The program will output "1 is less than 2". This feature is very useful in situations where various types of values ​​need to be returned.

To sum up, the application skills of switch statements in Golang functions are very rich. We can flexibly use these skills when needed to make the program more streamlined, efficient and easy to read.

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