[R] Odp: Using sample() with a data frame ?

Petr PIKAL petr.pikal at precheza.cz
Mon Aug 25 13:52:24 CEST 2008


Hi

you are not overly specific about what you really want but maybe

daf1[sample(1:83805, 10000), ]

This selects randomly 10000 rows from daf1

Is this what you want?

Regards
Petr

r-help-bounces at r-project.org napsal dne 25.08.2008 13:31:15:

> 
> I have a data frame (daf1), that holds +80000 records, and 10 variables 
(i.e. 
> 10 columns and some 80000 rows)
> 
> > length(daf1)
> [1] 10
> > length(daf1[,1])
> [1] 83805
> 
> I would like to sample() e.g. 10000 records from this. I use:
> 
> > daf2 <- sample(daf1, 1000, replace = FALSE, prob = NULL)
> Error in `[.data.frame`(x, .Internal(sample(length(x), size, replace,  : 

>   cannot take a sample larger than the population when 'replace = FALSE'
> 
> As length(daf1) is 10, it thinks I'm taking 10000 samples from a size 10 

> population... Arghhh
> 
> How do I go about sampeling from a data frame?
> 
> :-( Martin
> 
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