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?










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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?










    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?










      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






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      asked Nov 5 at 17:00









      Irakli

      314210




      314210
























          1 Answer
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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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