[R] How to call a value labels attribute?

[Heinz Tuechler]

Richard, Martin,

the example is not ideal, I see. I was strating from the question, how to
represent a metric categorical variable.
By "metric categorical variable" I intend a variable, which has only few
distinct values and an inherent metric. An example would be a risk score,
which classifies patients in several groups like "low, intermediate, high,
extreme" with corresponding risk estimates of "0, 1, 2, 5.5".
Other examples could be items in a questionnaire. These items often have
numerical values that may range from -5 to 5.
In some cases, like tables and box-plots these scores/items should be
treated like a factor (with labelled values), in other cases like
cox-regression or when forming an overall score they should be treated like
numeric variables.
I was asking for a convenient way to represent a variable like this, but
there was no response.
The crucial point is that the variables should retain their numerical
values and their value labels.
Without value labels they could be defined as factor and used or directly
or by as.numeric(), because the levels still represent the numerical
values, but as soon as labels are used, the original numerical values get
lost.


Thanks,

Heinz Tüchler

At 12:12 04.06.2006 -0400, Richard M. Heiberger wrote:
>How is what you are doing any different from factors?
>
>
>> x <- factor(c(1, 2, 3, 3, 2, 3, 1), labels=c("apple", "banana", "other"))
>> x
>[1] apple  banana other  other  banana other  apple 
>Levels: apple banana other
>> as.numeric(x)
>[1] 1 2 3 3 2 3 1
>> levels(x)[3] <- "birne"
>> x
>[1] apple  banana birne  birne  banana birne  apple 
>Levels: apple banana birne
>> 
>
>
>---- Original message ----
>>### not run
>>### pseudocode
>>x <- c(1, 2, 3, 3, 2, 3, 1)
>>value.labels(x) <- c(apple=1, banana=2, NA=3)
>>x
>>### desired result
>>apple banana  NA  NA banana NA apple
>>    1      2   3   3      2  3     1
>>
>>value.labels(x) <- c(Apfel=1, Banane=2, Birne=3) # redefine labels
>>x
>>### desired result
>>Apfel Banane Birne Birne Banane Birne Apfel
>>    1      2     3     3      2     3     1
>>
>>value.labels(x) # inspect labels
>>### desired result
>>Apfel Banane Birne
>>    1      2     3
>
>