multiple times addition of two columns with dplyr

Question

Assume I have a tibble (in my example here only with four columns). In real I have two hourly time series therefore 2 times 24 columns:

s1.x,...,s24.x, s1.y,...,s24.y

Now I want to sum up column s1.x with s1.y, s2.x with s2.y to s24.x with s24.y.

a <- tibble(s1.x=2:7, s2.x=3:8, s1.y=4:9, s2.y=5:10)

a %>% 
  mutate(s1.tot=s1.x+s1.y, s2.tot=s2.x+s2.y)

How can I do this in a short (and elegant way) for all 24 hours?

Answer 1

You can use Map function:

n = 2      # for your data, use n = 24
a[paste0("s", 1:n, ".tot")] = Map(`+`, a[paste0("s", 1:n, ".x")], a[paste0("s", 1:n, ".y")])

# A tibble: 6 × 6
   s1.x  s2.x  s1.y  s2.y s1.tot s2.tot
  <int> <int> <int> <int>  <int>  <int>
1     2     3     4     5      6      8
2     3     4     5     6      8     10
3     4     5     6     7     10     12
4     5     6     7     8     12     14
5     6     7     8     9     14     16
6     7     8     9    10     16     18