[R] entries that match a regexp

[Chuck Cleland]

Albert Vilella wrote:
> Hi all,
> 
> I am trying to filter the element of a df that start with "TF", like
> this:
> 
> alfa =
> c(123221,"TF13124",41243,"TF1234",32414,"TF13124","TF14333",2134123,"TF1234")
> beta =
> c("type_a","type_b","type_a","type_g","type_d","type_a","type_g","type_a","type_g")
> mydf = data.frame(alfa,beta)
> mydf
> tf = mydf[mydf$alfa %in% "TF",]
> 
> Shouldn't the %in% operator to the trick here?

tf <- mydf[grep("^TF", as.character(mydf$alfa)),]

> Thanks in advance,
> 
>     Albert.
> 
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Chuck Cleland, Ph.D.
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