R help - Aug 2005 - Extracting some rows from a data frame - lapses into a vector

I have a data frame with one column "x":
> str(data)
`data.frame':   20 obs. of  1 variable:
 $ x: num  0.0495 0.0986 0.9662 0.7501 0.8621 ...

Normally, I know that the notation dataframe[indexes,] gives you a new
data frame which is the specified set of rows. But I find:
> str(data[1:10,])
 num [1:10] 0.0495 0.0986 0.9662 0.7501 0.8621 ...

Here, it looks like the operation
      data[1:10,]
has converted it from type data frame into a numeric vector. Why does
this happen, and what can I do about it?

-- 
Ajay Shah                                                   Consultant
ajayshah at mayin.org                      Department of Economic Affairs
http://www.mayin.org/ajayshah           Ministry of Finance, New Delhi

Ajay Narottam Shah <ajayshah <at> mayin.org> writes:
> 
> I have a data frame with one column "x":
> 
> > str(data)
> `data.frame':   20 obs. of  1 variable:
>  $ x: num  0.0495 0.0986 0.9662 0.7501 0.8621 ...
....
> Here, it looks like the operation
>       data[1:10,]
> has converted it from type data frame into a numeric vector. Why does
> this happen, and what can I do about it?
Check parameter "drop" in the documentation of "[" or
Extract. The
simplification to a vector is default behavior for historical reasons, but 
somewhat confusing.

Dieter