R: Specifying a dataframe argument in a function

Question

I am trying to add a new column to a dataframe, however I need to create many columns for 5 or so dataframes. So I want to write a function. Since all the columns will be the same for each dataframe, this is what I had in mind:

 n = c(2,3,5)
 f = c("two", "three", "five")
 q = c(1,1.5,2.5)
 df= data.frame(n,f,q)
 fxn_foo <- function(x){
      x$egret <- (x$n)/2
 }

 fxn_foo(df)

 df$egret

Why does this produce Null? Are my arguments misspecified? Do I need to specify that the argument is a dataframe?

Zheyuan Li · Accepted Answer · 2016-09-16 00:35:22Z

3

You need a return statement:

fxn_foo <- function(x){
  x$egret <- (x$n)/2
  return(x)
  }

Then

df <- fxn_foo(df)

edited Sep 16, 2016 at 0:35

answered Sep 16, 2016 at 0:33

Zheyuan Li

73.8k18 gold badges194 silver badges266 bronze badges

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

Collectives™ on Stack Overflow

R: Specifying a dataframe argument in a function

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related