Re: [R] How can I extract part of the data with a selection criterion?

On May 9, 2013, at 7:06 PM, jpm miao wrote: > Hi, > > As an example, how can I get the data such that field a of ab, ab["a"], > equals 3? I expect the answer to be the union of 2 and 4, as > > Thanks, > >> a<-c(1,3,4,3,5,6,5) >> b<-c(2,4,6,7,3,1,2) >> ab<-data.frame(a,b) >> ab > a b > 1 1

Re: [R] How can I extract part of the data with a selection criterion?

Hi, Try ab[a==3,] You're selecting only rows for which a==3 (before the comma), and all columns (empty condition for column index, after the comma) Patrick 2013/5/9 jpm miao : > Hi, > >As an example, how can I get the data such that field a of ab, ab["a"], > equals 3? I expect the answer to

[R] How can I extract part of the data with a selection criterion?

Hi, As an example, how can I get the data such that field a of ab, ab["a"], equals 3? I expect the answer to be the union of 2 and 4, as Thanks, > a<-c(1,3,4,3,5,6,5) > b<-c(2,4,6,7,3,1,2) > ab<-data.frame(a,b) > ab a b 1 1 2 2 3 4 3 4 6 4 3 7 5 5 3 6 6 1 7 5 2 > ab[a==3] Error in `[.da