[R] levels() deletes other attributes

[Heinz Tuechler]

At 09:29 18.07.2005 -0500, Frank E Harrell Jr wrote:
>Heinz Tuechler wrote:
>> Dear All,
>> 
>> it seems to me that levels() deletes other attributes. See the following
>> example:
>> 
>> ## example with levels
>> f1 <- factor(c('level c','level b','level a','level c'), ordered=TRUE)
>> attr(f1, 'testattribute') <- 'teststring'
>> attributes(f1)
>> levels(f1) <- c('L-A', 'L-B', 'L-C')
>> attributes(f1)
>> 
>> If I run it, after assigning new levels, the class is only "factor" instead
>> of "ordered" "factor" and the $testattribute "teststring" is gone.
>> 
>> The same happens to the label() attribute of Hmisc.
>> 
>> ## example with levels and label
>> library(Hmisc)
>> f1 <- factor(c('level c','level b','level a','level c'), ordered=TRUE)
>> label(f1) <- 'factor f1'
>> attr(f1, 'testattribute') <- 'teststring'
>> attributes(f1)
>> levels(f1) <- c('L-A', 'L-B', 'L-C')
>> attributes(f1)
>> 
>> Should I expect this behaviour?
>
>Does the same thing happen when you do
>
>  attr(f1,'levels') <- c('L-A',...)
>
>Frank

No, it does not. With attr(f1,'levels') <- c('L-A', 'L-B', 'L-C') only the
levels are changed, all other attributes remain as before.
Heinz

>> 
>> Thanks
>> 
>> Heinz
>> 
>> # R-Version 2.1.0 Patched (2005-05-30)
>> # Windows98
>> 
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>
>
>-- 
>Frank E Harrell Jr   Professor and Chair           School of Medicine
>                      Department of Biostatistics   Vanderbilt University
>
>