R data frame, sampling with replacement while controling for two variables - r

Question

I have the following data frame in R, with three variables:
id<-c(1,2,3,4,5,6,7,8,9,10)
frequency<-c(1,2,3,4,5,6,7,8,9,10)
male<-c(1,0,1,0,1,0,1,0,1,0)
df<-data.frame(id,frequency,male)
For df mean frequency is 5.5 and 50% of observations are male. Now I want to take a random sample with replacement from df and with the same size, while mean frequency of the new sample is 4 and male's proportion remains constant.
I wonder if there is any way to do such thing in R.
Thanks in advance.

Answer 1

I cannot find any particular function for what you want. But it will give the results you want. The combination of 'repeat' and if function play the same role as while loop, and other line means do sampling size of 4.
repeat
{
df.sample = df[sample(nrow(df),size=4,replace=FALSE),]
if(mean(df.sample$frequency) == 4.5 & mean(df.sample$male) == 0.5){
break
}
}
The results is
> df.sample
id frequency male
4 4 4 0
2 2 2 0
9 9 9 1
3 3 3 1
For while loop,
while(!(mean(df.sample$frequency) == 4.5 & mean(df.sample$male) == 0.5)){
df.sample = df[sample(nrow(df),size=4,replace=FALSE),]
}