[Rd] sprintf error: "only 100 arguments allowed"

Tue Aug 25 11:08:52 CEST 2015

 From the sources:

#define MAXNARGS 100
/*               ^^^ not entirely arbitrary, but strongly linked to 
allowing %$1 to %$99 !*/


On 22/08/2015 04:21, Martin Bel wrote:
> I'm trying to apply a function defined in the VW R docs, that attemps to
> convert a data.table object to Vowpal Wabbit format. In the process i'm
> getting the error in printf mentioned in the subject.
> The original function is here:
> https://github.com/JohnLangford/vowpal_wabbit/blob/master/R/dt2vw.R
>
>
> Below there is a small example that reproduces the error. The function
> works great with smaller (less than 100 columns), as shown.
>
> Any suggestions of alternative methods to acomplish the same would be
> great, but I'm basically asking, is there a reason for the 100 arguments
> limitation?
>
>
> # Source this function#
> https://github.com/JohnLangford/vowpal_wabbit/blob/master/R/dt2vw.R
> # Here is a gist
> source('https://gist.githubusercontent.com/martinbel/a013c2bd2333b85eeb76/raw/7b68ede0385f3d8684a07854e8d6ca527b9cd441/dt2vw.R')
>
> library(data.table)
>
> X = cbind(matrix(rnorm(1:1010), nrow=10, ncol=101), sample(c(1, -1), 10, T))
> X = as.data.table(X)
> X[, weight:=ifelse(V102 == 1, 3, 1)]
> # check out function arguments
> head(dt2vw, 2)# function (data, fileName, namespaces = NULL, target,
> weight = NULL, #                 tag = NULL, hard_parse = F)
>
> namespaces = list(a = list(varName = sprintf('V%s',1:50), keepSpace=F),
>                    b = list(varName = sprintf('V%s',51:101), keepSpace=F))
>
> dt2vw(data=X, fileName='../out.vw', namespaces = NULL,
>        target='V102', weight = 'weight',
>        tag = NULL, hard_parse = F)
> ### error
> # [1] "sprintf('%f %f |A V1:%f V2:%f V3:%f V4:%f V5:%f V6:%f V7:%f
> V8:%f V9:%f V10:%f V11:%f V12:%f V13:%f V14:%f V15:%f V16:%f V17:%f
> V18:%f V19:%f V20:%f V21:%f V22:%f V23:%f V24:%f V25:%f V26:%f V27:%f
> V28:%f V29:%f V30:%f V31:%f V32:%f V33:%f V34:%f V35:%f V36:%f V37:%f
> V38:%f V39:%f V40:%f V41:%f V42:%f V43:%f V44:%f V45:%f V46:%f V47:%f
> V48:%f V49:%f V50:%f V51:%f V52:%f V53:%f V54:%f V55:%f V56:%f V57:%f
> V58:%f V59:%f V60:%f V61:%f V62:%f V63:%f V64:%f V65:%f V66:%f V67:%f
> V68:%f V69:%f V70:%f V71:%f V72:%f V73:%f V74:%f V75:%f V76:%f V77:%f
> V78:%f V79:%f V80:%f V81:%f V82:%f V83:%f V84:%f V85:%f V86:%f V87:%f
> V88:%f V89:%f V90:%f V91:%f V92:%f V93:%f V94:%f V95:%f V96:%f V97:%f
> V98:%f V99:%f V100:%f V101:%f ',V102, weight, V1, V2, V3, V4, V5, V6,
> V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, V17, V18, V19, V20,
> V21, V22, V23, V24, V25, V26, V27, V28, V29, V30, V31, V32, V33, V34,
> V35, V36, V37, V38, V39, V40, V41, V42, V43, V44, V45, V46, V47, V48,
> V49, V50, V51, V52, V53, V54, V55, V56, V57, V58, V59, V60, V61, V62,
> V63, V64, V65, V66, V67, V68, V69, V70, V71, V72, V73, V74, V75, V76,
> V77, V78, V79, V80, V81, V82, V83, V84, V85, V86, V87, V88, V89, V90,
> V91, V92, V93, V94, V95, V96, V97, V98, V99, V100, V101)"
> # Error in sprintf("%f %f |A V1:%f V2:%f V3:%f V4:%f V5:%f V6:%f V7:%f
> V8:%f V9:%f V10:%f V11:%f V12:%f V13:%f V14:%f V15:%f V16:%f V17:%f
> V18:%f V19:%f V20:%f V21:%f V22:%f V23:%f V24:%f V25:%f V26:%f V27:%f
> V28:%f V29:%f V30:%f V31:%f V32:%f V33:%f V34:%f V35:%f V36:%f V37:%f
> V38:%f V39:%f V40:%f V41:%f V42:%f V43:%f V44:%f V45:%f V46:%f V47:%f
> V48:%f V49:%f V50:%f V51:%f V52:%f V53:%f V54:%f V55:%f V56:%f V57:%f
> V58:%f V59:%f V60:%f V61:%f V62:%f V63:%f V64:%f V65:%f V66:%f V67:%f
> V68:%f V69:%f V70:%f V71:%f V72:%f V73:%f V74:%f V75:%f V76:%f V77:%f
> V78:%f V79:%f V80:%f V81:%f V82:%f V83:%f V84:%f V85:%f V86:%f V87:%f
> V88:%f V89:%f V90:%f V91:%f V92:%f V93:%f V94:%f V95:%f V96:%f V97:%f
> V98:%f V99:%f V100:%f V101:%f ",  : # only 100 arguments are allowed
> # works
> dt2vw(data=X[, 50:dim(X)[2], with=FALSE],
>        fileName='../out.vw', namespaces = NULL,
>        target='V102', weight = 'weight',
>        tag = NULL, hard_parse = F)
>
> system('head -3 ../out.vw')
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford
1 South Parks Road, Oxford OX1 3TG, UK