Hi Zhihua,
M <- data.frame (x=c(10, 13, 8, 11), y=c('A', 'B', 'A', 'A'))
which (M$x >= 10 & M$y == 'A')
# [1] 1 4
Hope it helps,
Nael
2008/3/7 N. Lapidus <[EMAIL PROTECTED]>:
> Hi Zhihua,
>
> M <- data.frame (x=c(10, 13, 8, 11), y=c('A', 'B', 'A', 'A'))
> which (M$x >= 10 & M$y == 'A')
> # [1] 1 4
>
> Hope it helps,
> Nael
>
>
> 2008/3/7 zhihuali <[EMAIL PROTECTED]>:
>
> >
> > Hi, netters,
> >
> > This is probably a rookie question but I couldn't find the answer after
> > hours of searching and trying.
> >
> > Suppose there'a a dataframe M:
> >
> > x y
> > 10 A
> > 13 B
> > 8 A
> > 11 A
> >
> > I want to locate the rows where x >=10 and y="A". I know how to do it to
> > vectors by using
> > which, but how to do it with the dataframe?
> >
> > Thank you very much!
> >
> >
> > Zhihua Li
> >
> > _________________________________________________________________
> > MSN ÖÐÎÄÍø£¬×îÐÂʱÉÐÉú»î×ÊѶ£¬°×Áì¾Û¼¯ÃÅ»§¡£
> >
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> >
> >
> > ______________________________________________
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> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
> >
>
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