[R] A printing "macro"

[Murray Jorgensen]

Thanks for these suggestions, Professor Ripley. It's interesting that
the function parameters in R are not truly "dummy" as they can effect
the result of a function.

Murray

Prof Brian Ripley wrote:
> ddisp <- function(dvar) {
>     yn <- substitute(dvar)
>     csqt <- eval.parent(substitute(chisq.test(G,dvar), list(dvar=yn)))
>     ....
> }
> 
> There are other ways, such as forming the cross-classification table, 
> setting its dimnames and passing that to chisq.test.
> 
> On Mon, 13 Nov 2006, Murray Jorgensen wrote:
> 
>> I am exploring the result of clustering a large multivariate data set
>> into a number of groups, represented, say, by a factor G.
>>
>> I wrote a function to see how categorical variables vary between groups:
>>
>> >  ddisp <- function(dvar) {
>> +  csqt <- chisq.test(G,dvar)
>> +  print(csqt$statistic)
>> +  print(csqt$observed)
>> +  print(round(csqt$expected))
>> +  round(csqt$residuals)
>> +  }
>> >
>> >  x <- ceiling(4*runif(100))
>> >  G <- gl(4,1,100)
>> >  ddisp(x)
>> X-squared
>>  6.235645
>>    dvar
>> G    1  2  3  4
>>   1 10  5  5  5
>>   2  6  9  5  5
>>   3  8  6  5  6
>>   4  7  4  4 10
>>    dvar
>> G   1 2 3 4
>>   1 8 6 5 6
>>   2 8 6 5 6
>>   3 8 6 5 6
>>   4 8 6 5 6
>>    dvar
>> G    1  2  3  4
>>   1  1  0  0 -1
>>   2 -1  1  0 -1
>>   3  0  0  0  0
>>   4  0 -1  0  1
>> Warning message:
>> Chi-squared approximation may be incorrect in: chisq.test(G, dvar)
>>
>> As I need to apply this function to a large number of variables x it
>> would be helpful if the function printed "x" rather than the formal
>> argument "dvar". I have a vague idea that things like deparse() and
>> substitute() will come into the solution but I have not yet come up with
>> the right incantation. Any help appreciated!
>>
>> Murray Jorgensen
>>
>>
> 

-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz                                Fax 7 838 4155
Phone  +64 7 838 4773 wk    Home +64 7 825 0441    Mobile 021 1395 862


-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz                                Fax 7 838 4155
Phone  +64 7 838 4773 wk    Home +64 7 825 0441    Mobile 021 1395 862