Code works but then fails when I try to turn it into a function (R)

January 1, 2023

I’m trying to create a function that will take in a table of data, convert it into a df, change the row names into a separate column, then delete the row names (else the row names will appear twice), and then rearrange the columns.

I can get this to work outside of a function but as soon as I put it into a function it doesn’t work.

Example data:

tb <- matrix(rep(2, times=8), ncol=2, byrow=TRUE)
tb <- as.table(tb)

Getting the desired result without creating a function:

n <- as.data.frame.matrix(tb)   
n$Variable <- row.names(n)   #Make new column containing row names. Call it Variable.
row.names(n) <- NULL   #Get rid of row names (otherwise the row names will appear twice)
n <- n[,c("Variable", "A", "B")]  #Rearrange columns

Attempting to do the same as above but make it into a function:
(I get this far and then realize the output is not what I expected. I would expect df with an additional column containing the row names at this stage. Instead, I just get the row names being printed)

dataframe_function<-function(data) {
  n <- as.data.frame.matrix(data)
  n$Variables <- row.names(n)
  #rownames(n) <- NULL
}

df1 <- dataframe_function(tb)
df1

Tried various things but can’t work out where I’m going wrong and can’t find a solution online. Can anyone help, please?

>Solution :

The function is incomplete. Below is all of the code previously not in a function.

dataframe_function <- function(data) {
  n <- as.data.frame.matrix(data)
  n$Variable <- row.names(n)
  row.names(n) <- NULL
  n[, c("Variable", "A", "B")]  #Rearrange columns
}

tb <- matrix(rep(2, times=8), ncol=2, byrow=TRUE)
tb <- as.table(tb)

df1 <- dataframe_function(tb)
df1
#>   Variable A B
#> 1        A 2 2
#> 2        B 2 2
#> 3        C 2 2
#> 4        D 2 2

^{Created on 2023-01-01 with reprex v2.0.2}