[R] filtering data frame based on two columns

[sun]

"sun" <flyhyena at yahoo.com.cn> wrote in message 
news:fm7mtb$tqk$1 at ger.gmane.org...
> Hi,
>
> I have a data frame df with column names a,b and c.
sorry for some typos.

should be subdf = df[df$a==1,]
and
subdf = df[df$a==1 && df$b ==2,]