mutate and rowSums exclude columns
dplyr, r
Solution
I'm only just learning dplyr, so perhaps it is because of version upgrades, but this does now work:
d %>% mutate(Total=rowSums(select(d,-Epsilon, -Alpha)))
These days, I usually see folks use the dot notation:
d %>% mutate(Total=rowSums(select(.,-Epsilon, -Alpha)))
A slightly more manageable example:
df2 = data.frame(A=sample(0:20,10), B=sample(0:20, 10), C=sample(0:20,10), D=LETTERS[1:10])
df2
A B C D
1 19 0 9 A
2 6 10 14 B
3 13 20 6 C
4 20 4 15 D
5 9 14 8 E
6 11 1 18 F
7 4 15 13 G
8 17 5 0 H
9 16 3 16 I
10 2 6 1 J
df2 %>% mutate(total=rowSums(select(.,-D)))
A B C D total
1 19 0 9 A 28
2 6 10 14 B 30
3 13 20 6 C 39
4 20 4 15 D 39
5 9 14 8 E 31
6 11 1 18 F 30
7 4 15 13 G 32
8 17 5 0 H 22
9 16 3 16 I 35
10 2 6 1 J 9
NOTE: The question you linked to has an updated answer that shows yet another new method that demonstrates some new dplyr features:
df2 %>% mutate(total=rowSums(select_if(., is.numeric)))
A B C D total
1 19 0 9 A 28
2 6 10 14 B 30
3 13 20 6 C 39
4 20 4 15 D 39
5 9 14 8 E 31
6 11 1 18 F 30
7 4 15 13 G 32
8 17 5 0 H 22
9 16 3 16 I 35
10 2 6 1 J 9
Problem
Similar to: mutate rowSums exclude one column but in my case, I really want to be able to use `select` to remove a specific column or set of columns I'm trying to understand why something of this nature, won't work. ``` d <- data.frame( Alpha = letters[1:26], Beta = rnorm(26), Epsilon = rnorm(26), Gamma = rnorm(26) ) ``` I thought this would work, but it's giving me a strange error: ``` # Total = Beta + Gamma d <- mutate(d,Total = rowSums(select(d,-Epsilon,-Alpha))) Error: All select() inputs must resolve to integer column positions. The following do not: * -structure(1:26, .Label = c("a", "b", "c", "d", "e", "f", "g", "h", "i... In addition: Warning message: In Ops.factor(1:26) : ‘-’ not meaningful for factors ``` I'd like to be able to do this in a long chain, and keep it "dplyr style"... it strikes me as odd that this is so difficult given that it's really straightforward without using typical dplyr syntax: ``` d$Total <- rowSums(select(d, -Alpha, -Epsilon)) # This works! ```