[R] extracting elements

[Prof Brian Ripley]

On Mon, 24 Sep 2001, luca laghi wrote:

> Equation constraints: optim()Dear R-users,
> is it possible to exract from a data frame the rows whose name contains a
> certain letter?
> Thank you, Luca

Is this what you want?

library(MASS)
data(hills)
hills[grep("r", row.names(hills)), ]

which gives the rows whose row names contain "r".

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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