R help - Dec 2008 - Extract rows from data frame based on row names from another data frame

Hi all,

Is there a function to extract row names from a data frame based on
row names from another data frame?  I can write a loop function to do
this, but this may be inefficient in terms of processing.

thanks for any information,

Wade

Hi

#Create data and data frames
x=rnorm(5,0,1)
y=rnorm(5,0,1)
z=rnorm(5,0,1)
d1=data.frame(x,y)
d2=data.frame(y,z)

#which variable name in d2 is a variable name in d1?
names(d2[names(d2)%in%names(d1)]) # it's y

#give me the columns of d2 that have variable names
#that are also variable names in d1

d2[names(d2)==names(d2[names(d2)%in%names(d1)])]

#check
d2$y

Cheers,
Daniel


-------------------------
cuncta stricte discussurus
-------------------------

-----Urspr?ngliche Nachricht-----
Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im
Auftrag von Wade Wall
Gesendet: Thursday, December 11, 2008 3:59 PM
An: r-help at stat.math.ethz.ch
Betreff: [R] Extract rows from data frame based on row names from
anotherdata frame

Hi all,

Is there a function to extract row names from a data frame based on row
names from another data frame?  I can write a loop function to do this, but
this may be inefficient in terms of processing.

thanks for any information,

Wade

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