Sum across columns in same row using column name R

Question

I have a dataset similar to what is below:

ID | Var1 | Var2 | Var3 | Sum
-----------------------------
1     3      4      7      
2     1      2      3     
3     3      5      16

I need to create the Sum variable above. I need to be able to sum different values in a series of variables. For above, it'd be 14, 6, and 24, for rows 1, 2, and 3. I want to do it with something like

df$Sum <- sum('Var1', 'Var2', 'Var3')

I can't seem to find an example this simple. Everything I have found involved code that I either do not understand, or it's able to deal with situations far more complex than what I've got, and will have for the foreseeable future. I realize it would probably behoove me to learn something more in depth, but at this point I would like it to be simple. I have tried sum, aggregate, and rowSum, and none of them have gotten me what I want.

Any help is appreciated.

@Jaap please provide link to the duplicate question. I looked here first, and didn't find anything this simple and easy to use. Everything was more complex, and that's not what I was looking for. — Adam_S, Mar 16 '18 at 18:38

AnnVyrgyl · Accepted Answer · 2018-03-16T18:25:32.913

2

Try:

df$Sum <- (df$Var1 + df$Var2 + df$Var3)

edited Mar 16 '18 at 18:25

answered Mar 16 '18 at 18:15

AnnVyrgyl

56
6

The first one will not do what they are asking. The second one is correct, although the parentheses are unnecessary. – user295691 Mar 16 '18 at 18:21
Edited to remove the suggestion that won't work. Important part is that the need to add "df$" when calling out the variables they want to sum. – AnnVyrgyl Mar 16 '18 at 18:27
PERFECT. Thank you AnnVyrgyl !!! – Adam_S Mar 16 '18 at 18:29

Sum across columns in same row using column name R

1 Answers1