Creating a new column to a data frame using a formula from another variable

Question

I want to create a new column to a data frame using a formula from another variable.
Example:
I have a data set \"aa\" is;

x    y 
2    3 
4             


        

Answer 1

You should probably read some basic tutorials on R other than An Introduction to R as despite what is written there the $ notation is more sensible and easier to understand than attach/detach. Try this in the meantime.

aa <- data.frame(x = c(2, 4, 6), y = c(3, 5, 7))

Which gives:

> aa
  x y
1 2 3
2 4 5
3 6 7

Then enter:

aa$z <- (aa$x + aa$y) - 2

Which gives:

> aa
  x y  z
1 2 3  3
2 4 5  7
3 6 7 11