Passing list of parameters in a function in R

Question

Im new in this page. I have been working with this code with no success.

I have a list of parameters.

price<-seq(10,100,length=10)

alfa<-seq(2,3,length=4)

beta<-seq(0.1,0.2,length=4)

the list is:

[[1]]
 [1]  10  20  30  40  50  60  70  80  90 100

[[2]]
[1] 2.000000 2.333333 2.666667 3.000000

[[3]]
[1] 0.1000000 0.1333333 0.1666667 0.2000000

and what I want to to is to create a function that, for each price, do the following. I tried with lapply function with no results.

price*beta[1]+alfa[1]

price*beta[2]+alfa[2]

price*beta[3]+alfa[3]

price*beta[4]+alfa[4]

Thanks!

Answer 1

You can usually write the function outside of the lapply() function like this:

price<-seq(10,100,length=10)
alfa<-seq(2,3,length=4)
beta<-seq(0.1,0.2,length=4)

f <- function(price) c(price*beta[1]+alfa[1], price*beta[2]+alfa[2], price*beta[3]+alfa[3], price*beta[4]+alfa[4])

lapply(price, f)

Does this work?

Answer 2

Please provide your lapply code ..

here one more way can possible.. code is

pr <- function(){
new_val <- 0

new_val <- price*alfa+beta

return(new_val)
}

if you want you can use this.

Answer 3

A more natural function for this is Mapply which takes in vector arguments and applies a function to elements by position.

mapply(function(x, y, price) (price * y) + x, alfa, beta,
       MoreArgs=list("price"=price), SIMPLIFY=FALSE)
[[1]]
 [1]  3  4  5  6  7  8  9 10 11 12

[[2]]
 [1]  3.666667  5.000000  6.333333  7.666667  9.000000 10.333333 11.666667 13.000000 14.333333 15.666667

[[3]]
 [1]  4.333333  6.000000  7.666667  9.333333 11.000000 12.666667 14.333333 16.000000 17.666667 19.333333

[[4]]
 [1]  5  7  9 11 13 15 17 19 21 23

Here, the MoreArgs argument is used to feed the generic function price as a vector rather than element by element. You could also use the wrapper for mapply , Map which always returns a list. This negates the need for the SIMPLIFY argument:

Map(function(x, y, price) (price * y) + x, alfa, beta, MoreArgs=list(price=price))
[[1]]
 [1]  3  4  5  6  7  8  9 10 11 12

[[2]]
 [1]  3.666667  5.000000  6.333333  7.666667  9.000000 10.333333 11.666667 13.000000 14.333333 15.666667

[[3]]
 [1]  4.333333  6.000000  7.666667  9.333333 11.000000 12.666667 14.333333 16.000000 17.666667 19.333333

[[4]]
 [1]  5  7  9 11 13 15 17 19 21 23