[R] direct data frame entry

Liaw, Andy andy_liaw at merck.com
Wed Jun 9 21:40:02 CEST 2004


?data.frame says:

Usage:

     data.frame(..., row.names = NULL, check.rows = FALSE, check.names =
TRUE)

Arguments:

     ...: these arguments are of either the form 'value' or
          'tag=value'.  Component names are created based on the tag
          (if present) or the deparsed argument itself.

which means you need to do the `transpose' of what you did: give
data.frame() columns, rather than rows.  E.g.,

dat <- data.frame(x=factor(c("A", "B", "A", "C"), y=1:4,
rownames=LETTERS[1:4])

It's hard to build a data frame by row, because one needs to check and make
sure data in each column are consistent, that data in a factor column have
the right levels, etc.

Andy

> From: ivo welch
> 
> hi:  I searched the last 2 hours for a way to enter a data frame 
> directly in my program.  (I know how to read from a file.)  
> that is, I 
> would like to say something like
> 
>     d <- this.is.a.data.frame(   c("obs1name", 0.2, 0.3),
>                                           c("obs2name", 0.4, 1.0),
>                                           c("obs3name", 0.6, 2.0) , 
> varnames=c("name", "val1", "val2")  );
> 
> everything I have tried sofar (usually, building with rbind and then 
> names(d)) has come out with factors for the numbers, which is 
> obviously 
> not what I want.   this must be a pretty elementary request, so it 
> should probably be an example under data.frame (or read.table).  of 
> course, it is probably somewhere---just I have do not remember it and 
> could not find it after 2 hours of searching.  I also tried 
> the r-help 
> archives---at the very least, I hope we will get the answer there for 
> future lookups.
> 
> regards, /iaw
> 
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