问题
Possible Duplicate:
Standard way to remove multiple elements from a dataframe
I know in R that if you are searching for a subset of another group or matching based on id you'd use something like
subset(df1, df1$id %in% idNums1)
My question is how to do the opposite or choose items NOT matching a vector of ids.
I tried using ! but get the error message
subset(df1, df1$id !%in% idNums1)
I think my backup is to do sometime like this:
matches <- subset(df1, df1$id %in% idNums1)
nonMatches <- df1[(-matches[,1]),]
but I'm hoping there's something a bit more efficient.
回答1:
The expression df1$id %in% idNums1 produces a logical vector. To negate it, you need to negate the whole vector:
!(df1$id %in% idNums1)
来源：https://stackoverflow.com/questions/9852832/r-not-in-subset