Using lapply to run a function with multiple parameters

Question

I have a function that I'd like to run with a variety of parameters (see p_space in example). I can easily do this using a for loop. However, because I am planning to use parellel processing at a later date lapply seems like the way to go. Does anyone know how I can do this? My attempts don't seem to work at all!

example code:

as <- c(1,2)  # limit for K
bs <- c(3,4)
cs <- c(2,3)  # distribution of food sources ('random'/'clustered')

p_space <- list ()
for (a in as){
  for (b in bs){
    for (c in cs){
      p_space[[length(p_space)+1]] <- c(a,b,c)
    }
  }
}
made_up <- function(a, b, c){
  return(a * b * c)
}

My attempt to do this:

lapply(p_space, made_up(i) p_space[[i]])

My desired output is a dataframe/matrix/list with the results of the made_up function on all of the parameter sets in p_space.

How I would do this using for loops

 results <- list()

for (a in as){
  for (b in bs){
    for (c in cs){
      results[[length(results) + 1 ]] <- c(a*b*c,a,b,c)
    }}}

What is your expected output ?

Julien Navarre
– Julien Navarre

2018-02-22 17:24:24 +00:00
Commented Feb 22, 2018 at 17:24 — Julien Navarre
– Julien Navarre, Commented Feb 22, 2018 at 17:24
added to the question. Sorry if it wasn't clear

unknown
– unknown

2018-02-22 17:28:09 +00:00
Commented Feb 22, 2018 at 17:28 — unknown
– unknown, Commented Feb 22, 2018 at 17:28

steveLangsford · Accepted Answer · 2018-02-22 17:35:04Z

1

Maybe pass a vector to made_up and then extract a,b and c?

made_up <- function(pvec){
  return(pvec[1]*pvec[2]*pvec[3])
}

lapply(p_space,made_up)

answered Feb 22, 2018 at 17:35

steveLangsford

6465 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

unknown Over a year ago

amazing! This works. Do you know if there is a way that you can extract the parameter values that were used in each run as well?

unknown Over a year ago

actually, never mind I did this using return(list(pvec[1],pvec[2],pvec[3],pvec[1]*pvec[2],pvec[3])). Thanks for your help

Collectives™ on Stack Overflow

Using lapply to run a function with multiple parameters

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related