A list in a function should return several outcome, amoung them a data frame

Question

I have created a dataframe comprising of the following elements:

set.seed(1)

a <- rnorm(1:5,0,1)

b <- rnorm(1:5,0,1)

c <- rnorm(1:5,0,1)

df <- data.frame(a,b,c)

Now I want to have a list that should return a list, first the name of the column and then the data frame. But it doesnt work to return the data frame. 

test <- function(i){

num <- list()

num[1] <- colnames(df)[i]

num[2] <- df

return(num)

}

test(1)

[[1]]

[1] "a"

[[2]]

[1] -0.6264538  0.1836433 -0.8356286  1.5952808  0.3295078

Warning message:

In num[2] <- df :

  number of items to replace is not a multiple of replacement length

Answer 1

What I think is you want to return value of only that respective column.So for doing that you can refer the following code:

test <- function(df, i){

  list(name = colnames(df)[i], value = df[[i]])

}

test(df, 1)

#$name

#[1] "a"

#$value

#[1] -0.63  0.18 -0.84  1.60  0.33

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