[R] dropping rows

Douglas Bates bates at stat.wisc.edu
Thu Dec 2 01:42:57 CET 2004

Tobias Muhlhofer wrote:
> Hi!
> Sorry for asking a trivial questions, but I can't seem to figure this out.
> I have a dataframe called master containing 30-odd variables.
> In this dataframe, I have observations across these 30 variables from 
> 1930 to 2003 (I've made a "year" variable). How can I drop all rows for 
> which the year is less than 1960? I'm assuming something with ifelse() 
> but I can't quite figure it out.
> I would appreciate a suggestion of some syntax.

In R this is called subsetting and the simplest way to do this is with 
the subset function.

older <- subset(master, year < 1960)

See ?subset for more variations on this theme.

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