使用开关的 Golang 程序，多值情况
原文:https://www . geesforgeks . org/golang-program-the-use-switch-multi-value-cases/
Switch 语句是一个多路分支，它提供了一种过长的 if-else 比较的替代方法。它根据表达式的值或单个变量的状态，从多个块的列表中选择要执行的单个块。使用多值情况的 switch 语句对应于在单个情况下使用多个值的。这是通过用逗号分隔案例中的多个值来实现的。
例 1:
// Golang program to illustrate the
// use of switch with multiple value cases
package main
import (
"fmt"
)
func main() {
// string to input month from user
var month string
fmt.Scanln(&month)
// switch case for predicting
// seasons for month entered
// each switch case has more
// than one values
switch month {
case "january", "december":
fmt.Println("Winter.")
case "february", "march":
fmt.Println("Spring.")
case "april", "may", "june":
fmt.Println("Summer.")
case "july", "august":
fmt.Println("Monsoon.")
case "september", "november":
fmt.Println("Autumn.")
}
}
Input : january
Output : Winter.
Input : september
Output : Autumn.
我们不是在同一个季节的几个月里制作不同的单个案例，而是在不同的月份制作相同的产品。这就节省了我们编写冗余代码的时间。
例 2:
// Golang program to illustrate the
// use of switch with multiple value cases
package main
import (
"fmt"
)
func main() {
// integer to input number from
// user (only 1-10)
var number int
fmt.Scanln(&number)
// switch case for predicting
// whether the number is even or odd
// each switch case has more
// than one values
switch number {
case 2, 4, 6, 8, 10:
fmt.Println("You entered an even number.")
case 1, 3, 5, 7, 9:
fmt.Println("You entered an odd number.")
}
}
Input : 6
Output : You entered an even number.
Input : 5
Output : You entered an odd number.
我们不需要写 10 个不同的案例来检查输入的数字是否为偶数，我们可以简单地使用多个案例值在两个开关案例中做同样的事情。
例 3:
// Golang program to illustrate the
// use of switch with multiple value cases
package main
import (
"fmt"
)
func main() {
// character input (a-z or A-Z)
var alphabet string
fmt.Scanln(&alphabet)
// switch case for predicting
// whether the character is
// uppercase or lowercase
// each switch case has more
// than one values
switch alphabet {
case "a", "b", "c", "d", "e", "f", "g", "h", "i",
"j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
"u", "v", "w", "x", "y", "z":
fmt.Println("Lowercase alphabet character.")
case "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",
"K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
"U", "V", "W", "X", "Y", "Z":
fmt.Println("Uppercase alphabet character.")
}
}
Input : g
Output : Lowercase alphabet character.
Input : F
Output : Uppercase alphabet character.
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