Adding vector from simulations in R

Question

i am trying to simulate data using R.When i run the code below it creates an array with all the 10000 iterations from rexp. How can I have another vector within x to store the values from rpois(1,1,2) in code below.

set.seed(0) 
system.time( x <- replicate(10000 ,rexp(rpois(1,1.2), rate=0.1)) )

Currently the first few output values from the code are.

   [[1]]
   [1] 2.669865 0 0 4.150295

   [[2]]
   [1] 0 4.150295 

   [[3]]
   [1]2.669865 14.759684  4.150295  4.635850 11.200548

so in the revised code I would like to include count values from rpois(1,1.2)so the above output will be

   [[1]]
   [1] 4 2.669865 0 0 4.150295

   [[2]]
   [1] 2 0 4.150295 

   [[3]]
   [1] 5 2.669865 14.759684  4.150295  4.635850 11.200548

Answer 1

We get the length of each element in the list with lengths , concatenate ( c ) the corresponding element in the 'x' using Map .

Map(c, lengths(x), x)
#[[1]]
#[1] 4.000000 2.669805 0.000000 0.000000 4.150925

#[[2]]
#[1] 2.000000 0.000000 4.150295

#[[3]]
#[1]  5.000000  2.669865 14.759684  4.150295  4.635800 11.200548

data

x <- list(c(2.669805, 0, 0, 4.150925), c(0, 4.150295), 
   c(2.669865, 14.759684, 4.150295, 4.6358, 11.200548))

Answer 2

here's a solution using lapply :

li <- list(c(2.669865, 0, 0, 4.150925), c(0, 4.150295), c(2.669865, 14.759684, 4.150295, 4.635850, 11.200548))
lapply( li ,function(x){c(length(x),x)})