R-如何从两个不同的概率中随机选择 select？

Question

I am looking to assign two different weighted probabilities (0.3 and 0.7). Each time (loop?) i want R to randomly select one of the two weighted probabilities. Then i need those data output in a dataframe.

I've tried a number of ways with no success. I am still a beginner.

Here is my noob code which doesn't work. I tried to sample the columns randomly. Thanks.

roll_it<-c(1:100)
n70<- 1; p70<-7/10
n30<- 1; p30<-3/10

for( i in roll_it){ 
        result <- c(rbinom(n30, 1, p30), rbinom(n70, 1, p70))
        
        print(result)}

sample(result(1:2,), size=2, replace = F)

Answer 1

If I understand your your goal correctly you don't need to use a loop at all. Just create two samples and then sample from that mixture distribution.

set.seed(1)

cc <- cbind(rbinom(100, 1, 0.3), rbinom(100, 1, 0.7))
colMeans(cc)
# [1] 0.32 0.70
sample(cc, 2)
# [1] 0 0

Answer 2

Use sample() .

roll_it < -c(1:100)
n70<- 1
n30<- 1

probabilities <- c(0.3, 0.7)
for(i in roll_it){ 
    result <- rbinom(x = n30, size = 1, prob = sample(probabilities, 1))
    print(result)
}

May I add, I'm not sure why are you using n30 and n70. Could you just use one of them?