Remove values from a dataset based on a vector of those values

Question

I have a dataset that looks like this, except it\'s much longer and with many more values:

dataset <- data.frame(grps = c(\"a\",\"b\",\"c\",\"a\",\"d\",\"b\"         


        

Answer 1

Try:

dataset[!(dataset$grps %in% remove),]

Answer 2

There's also subset:

subset(dataset, !(grps %in% remove))

... which is really just a wrapper around [ that lets you skip writing dataset$ over and over when there are multiple subset criteria. But, as the help page warns:

This is a convenience function intended for use interactively. For programming it is better to use the standard subsetting functions like ‘[’, and in particular the non-standard evaluation of argument ‘subset’ can have unanticipated consequences.

I've never had any problems, but the majority of my R code is scripting for my own use with relatively static inputs.

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2013-04-12

I have now had problems. If you're building a package for CRAN, R CMD check will throw a NOTE if you have use subset in this way in your code - it will wonder if grps is a global variable, even though subset is evaluating it within dataset's environment (not the global one). So if there's any possiblity your code will end up in a package and you feel squeamish about NOTEs, stick with Rcoster's method.