R: How to output a recursive or iterative function/map output into a vector?











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I'd like to feed the output of a user-defined function back to its input (a recursive map), run this iteration N times, and save the output of every iteration in a vector. This is simple to do with "for" loop



my_fun <- function(x) {x/3 +1} # a user-defined function (trivial example)



my_l <- c()



x <- 0 # initial condition



for(i in 1:10) {

  x <- my_fun(x)

  my_l[i] <- x

}



print(my_l)



>[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975


The above works but seems crude. Is there a shorter way to do it? Perhaps with tidyverse/purrr?






r loops recursion purrr







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    up vote
    1
    down vote

    favorite












    I'd like to feed the output of a user-defined function back to its input (a recursive map), run this iteration N times, and save the output of every iteration in a vector. This is simple to do with "for" loop



    my_fun <- function(x) {x/3 +1} # a user-defined function (trivial example)
    

    
my_l <- c()
    

    
x <- 0 # initial condition
    

    
for(i in 1:10) {
    
  x <- my_fun(x)
    
  my_l[i] <- x
    
}
    

    
print(my_l)
    

    
>[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975


    The above works but seems crude. Is there a shorter way to do it? Perhaps with tidyverse/purrr?






    r loops recursion purrr







    share|improve this question
























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      I'd like to feed the output of a user-defined function back to its input (a recursive map), run this iteration N times, and save the output of every iteration in a vector. This is simple to do with "for" loop



      my_fun <- function(x) {x/3 +1} # a user-defined function (trivial example)
      

      
my_l <- c()
      

      
x <- 0 # initial condition
      

      
for(i in 1:10) {
      
  x <- my_fun(x)
      
  my_l[i] <- x
      
}
      

      
print(my_l)
      

      
>[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975


      The above works but seems crude. Is there a shorter way to do it? Perhaps with tidyverse/purrr?






      r loops recursion purrr







      share|improve this question













      I'd like to feed the output of a user-defined function back to its input (a recursive map), run this iteration N times, and save the output of every iteration in a vector. This is simple to do with "for" loop



      my_fun <- function(x) {x/3 +1} # a user-defined function (trivial example)
      

      
my_l <- c()
      

      
x <- 0 # initial condition
      

      
for(i in 1:10) {
      
  x <- my_fun(x)
      
  my_l[i] <- x
      
}
      

      
print(my_l)
      

      
>[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975


      The above works but seems crude. Is there a shorter way to do it? Perhaps with tidyverse/purrr?






      r loops recursion purrr




      r loops recursion purrr






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 5 at 17:00









      Irakli

      314210




      314210
























          1 Answer
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          up vote
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          We can use accumulate



          library(tidyverse)
          
accumulate(1:10, ~ my_fun(.x), .init = 1)
          
#[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975 1.499992



          Or with Reduce from base R



          Reduce(function(x, y) my_fun(x), 1:10, init = 1, accumulate = TRUE)





          share|improve this answer





















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            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes








            up vote
            4
            down vote



            accepted










            We can use accumulate



            library(tidyverse)
            
accumulate(1:10, ~ my_fun(.x), .init = 1)
            
#[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975 1.499992



            Or with Reduce from base R



            Reduce(function(x, y) my_fun(x), 1:10, init = 1, accumulate = TRUE)





            share|improve this answer

























              up vote
              4
              down vote



              accepted










              We can use accumulate



              library(tidyverse)
              
accumulate(1:10, ~ my_fun(.x), .init = 1)
              
#[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975 1.499992



              Or with Reduce from base R



              Reduce(function(x, y) my_fun(x), 1:10, init = 1, accumulate = TRUE)





              share|improve this answer























                up vote
                4
                down vote



                accepted







                up vote
                4
                down vote



                accepted






                We can use accumulate



                library(tidyverse)
                
accumulate(1:10, ~ my_fun(.x), .init = 1)
                
#[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975 1.499992



                Or with Reduce from base R



                Reduce(function(x, y) my_fun(x), 1:10, init = 1, accumulate = TRUE)





                share|improve this answer












                We can use accumulate



                library(tidyverse)
                
accumulate(1:10, ~ my_fun(.x), .init = 1)
                
#[1] 1.000000 1.333333 1.444444 1.481481 1.493827 1.497942 1.499314 1.499771 1.499924 1.499975 1.499992



                Or with Reduce from base R



                Reduce(function(x, y) my_fun(x), 1:10, init = 1, accumulate = TRUE)






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 5 at 17:02









                akrun

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