I'm working with a tibble that consists of a matrix transformed into long format. The matrix is simply all-vs-all values output of a function. However the output of the function differs depending on the order of provided values i.e. function(x,y) != function(y,x). Therefore I'm trying to mutate tibble so that the additional column would contain the higher outcome of the two: function(x,y) or function(y,x). I'm struggling with this but I'm pretty sure that there is an elegant solution which I cannot see.
df1 <- tibble(n1 = rep(c('a', 'b', 'c'), each=3), n2 = rep(c('a', 'b', 'c'),3), val = sample(1:100,9))
df1
n1 n2 v1
a a 41
a b 94
a c 40
b a 85
b b 82
b c 35
c a 66
c b 70
c c 76
So the result of mutate would look like this:
n1 n2 v1 v1.high
a a 41 41
a b 94 94
a c 40 66
b a 85 94
b b 82 82
b c 35 70
c a 66 66
c b 70 70
c c 76 76
One option using dplyr could be:
df1 %>%
group_by(grp = paste(pmax(n1, n2), pmin(n1, n2))) %>%
mutate(val_high = max(val)) %>%
ungroup() %>%
select(-grp)
n1 n2 val val_high
<chr> <chr> <int> <int>
1 a a 38 38
2 a b 37 75
3 a c 34 34
4 b a 75 75
5 b b 91 91
6 b c 54 54
7 c a 3 34
8 c b 16 54
9 c c 46 46