[R] Extracting some rows from a data frame - lapses into a vector

Dieter Menne dieter.menne at menne-biomed.de
Tue Aug 16 08:26:51 CEST 2005


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




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