想要选择一个随机数，直到所有数字都通过后才选择

Question

I'm looking to pick a random number from 1-6 but if for example 1 is picked by the program I want to make sure it is not again used until 2-6 has been picked. I want to do this in order to have a chance to go through all options instead of having the same option 2 or maybe 3 times in a row since there are only 6 options. Any ideas please?

//choose random number for recipe
rand.Seed(time.Now().UTC().UnixNano())
myrand := random(1, 6)
fmt.Println(myrand)

...

function that processes it

//random number function
func random(min, max int) int {
    return rand.Intn(max-min) + min

}

The part of my program that uses myrand from each run is used in a if statement and is tied to the recipe that will be picked for the day

//choose random number for recipe
rand.Seed(time.Now().UTC().UnixNano())
myrand := random(1, 6)
fmt.Println(myrand)

//test below of random replacement
list := rand.Perm(6)
for i, _ := range list {
    fmt.Printf("%d
", list[i]+1)
}

//logic for recipe to choose
if myrand == 1 {
    fmt.Println(1)
    printRecipeOfTheDay(recipe1)
} else if myrand == 2 {
    fmt.Println(2)
    printRecipeOfTheDay(recipe2)
} else if myrand == 3 {
    fmt.Println(3)
    printRecipeOfTheDay(recipe3)
} else if myrand == 4 {
    fmt.Println(4)
}

}

I'm wondering if I'm doing something incorrectly ? I'm not sure how I can use the list on every run to generate a new number (myrand) and the program will be able to remember what the last number (myrand) was when it ran the previous time?

Answer 1

You can use rand.Perm(6) and then loop through the result.

For example, here is code to print the numbers 1-6 in a random order, with no repeats:

package main
import "fmt"
import "math/rand"

func main(){
    list := rand.Perm(6);
    for i, _ := range list {
        fmt.Printf("%d
", list[i]+1);
    }
}

Note that we've added 1 to everything, since Perm(6) returns 0-5 and you want 1-6. After you've used all six, call rand.Perm(6) again for six new numbers.