Dataframe create new column based on other columns

Question

I have a dataframe:

df <- data.frame(\'a\'=c(1,2,3,4,5), \'b\'=c(1,20,3,4,50))
df
    a    b
1   1    1
2   2   20
3   3    3
4   4    4
5   5   50
         


        

Answer 1

Using dplyr package:

library(dplyr)

df <- df %>% 
  mutate(c = if_else(a == b, a + b, b - a))

df
#   a  b  c
# 1 1  1  2
# 2 2 20 18
# 3 3  3  6
# 4 4  4  8
# 5 5 50 45