na.omit function syntax

[FIC]

df <- data.frame(stringsAsFactors = FALSE,
x = c(NA, "3", "NA", "7", "1", "2", "3"),
y = 1:7)

To omit all NA's in column 3:
data.new <- na.omit (data[-3])

How do you know that the [-3] refers to the 3rd column, and not the 3rd row?

[Yarnabrina]

This has nothing to do with the na.omit function.

Check the documentation of Extract.data.frame:

When [ and [[ are used with a single vector index (x[i] or x[[i]]), they index the data frame as if it were a list

Please note that you are using data, but you haven't defined it yet.