Randomly subset of data with dplyr

Question

This is not what I want. I want to extract groups randomly from a data frame not the random rows from each subset.

For example,

xx <- rep(rep(seq(0,800,200),each=10),times=2)
       yy<-c(replicate(2,sort(10^runif(10,-1,0),decreasing=TRUE)),replicate(2,sort(10^runif(10,-1,0),decreasing=TRUE)), replicate(2,sort(10^runif(10,-2,0),decreasing=TRUE)),replicate(2,sort(10^runif(10,-3,0),decreasing=TRUE)), replicate(2,sort(10^runif(10,-4,0), decreasing=TRUE)))    
       V <- rep(seq(100,2500,length.out=10),times=2)
       No <- rep(1:10,each=10)
       df <- data.frame(V,xx,yy,No)
library(dplyr)
    random <-  df %>%
            group_by(No)%>%
        sample_n(5,replace=T)  

Answer 1

Maybe this is what you want:

# sample from distinct values of No
my_groups <- 
  df %>% 
  select(No) %>% 
  distinct %>% 
  sample_n(5)

# merge the two datasets
my_df <-
  left_join(my_groups, df)