While an avid fan of dplyr, I'm still puzzled by some of the NSE issues that inevitably arise when I try to do something of non-trivial complexity.
Case in point: finding row sums of a subset of columns.
temp <- data.frame(A = 1:3, B = 4:6, C = 8:10)
This works:
temp %>% {rowSums(select(., B:C), na.rm = TRUE)}
and this (SE version) works:
temp %>% mutate(Sum = rowSums(select_(., .dots = "B:C"), na.rm = TRUE))
but this does not work:
temp %>% mutate(Sum = rowSums(select(., B:C), na.rm = TRUE))
Error: Position must be between 0 and n
In addition: Warning messages:
1: In 4:6:8:10 : numerical expression has 3 elements: only the first used
2: In 4:6:8:10 : numerical expression has 3 elements: only the first used
Why?
