How can I calculate the difference between all values of a two columns.
X Mass_1 Mass_2
1 109.8 203.4
2 306.7 305.5
3 658.7 446.5
I need the difference of Mass_1 against all numbers of Mass_2
> X Mass_1 Mass_2_1 Mass_2_2 Mass_2_3
> 1 109.8 (109.8-203.4) (109.8-305.5) (109.8-446.5)
> 2 306.7 (306.7-203.4) (306.7-305.5) (306.7-446.5)
> 3 658.7 (658.7-203.4) (658.7-305.5) (658.7-446.5)
You may use lapply -
cols <- paste0('Mass_2_', seq(nrow(df)))
df[cols] <- lapply(df$Mass_2, function(x) df$Mass_1 - x)
df
# X Mass_1 Mass_2 Mass_2_1 Mass_2_2 Mass_2_3
#1 1 109.8 203.4 -93.6 -195.7 -336.7
#2 2 306.7 305.5 103.3 1.2 -139.8
#3 3 658.7 446.5 455.3 353.2 212.2
Or with outer -
df[cols] <- outer(df$Mass_1, df$Mass_2, `-`)
data
df <- structure(list(X = 1:3, Mass_1 = c(109.8, 306.7, 658.7), Mass_2 = c(203.4,
305.5, 446.5)), class = "data.frame", row.names = c(NA, -3L))