You can count the number of fields per line in a comma/tab/whatever delimited text file using utils::count.fields.
Here's a reproducible example:
d <- data.frame(
x = c(1, NA, 3, NA, 5),
y = c(NA, "b", "c", NA, NA),
z = c(NA, "beta", "gamma", NA, "epsilon")
)
fname <- "test.csv"
write.csv(d, fname, na = "", row.names = FALSE)
count.fields(fname, sep = ",")
## [1] 3 3 3 3 3 3
I want to calculate the number of non-empty fields per line. I can do this in a clunky way by reading in everything and counting the number of values that aren't NA.
d2 <- read.csv(fname, na.strings = "")
rowSums(!is.na(d2))
## [1] 1 2 3 0 2
I'd really like a way of scanning the file (like count.fields) so I can target specific sections to read in.
Is there a better way of counting the number of non-empty fields in a delimited file?