Hi,

   I have a vector f with some negative columns. I remember that there is
an easy expression that can find out negative items. Can someone tell me
how I can do it?

   It seems to be
   f[i such that f[i]<0 ...]

   Thanks,

Miao

> d<-1:7
> f<-(-2)^d
> f
[1]   -2    4   -8   16  -32   64 -128

	[[alternative HTML version deleted]]

