It depends on which 20 you want.
If you have a data.frame called 'test.df', you can do:
#first 20
test.df[20, ]
-or-
head(test.df, 20)
#random 20
test.df[sample(nrow(test.df), 20), ]
None of this was tested, but it should be a start.
--Erik
Matev? Pavli? wrote:> Hi,
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> I am sure that can be done in R....
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> How would i delete all but let say 20 observations in data.frame?
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> Thank you, M
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