1

我正在尝试使用 R 包 mlr 的第一个示例，可以在此处找到。但我收到以下错误消息：

> lrn = makeLearner("classif.lda") 
Error in substr(packs, 1L + (force.load | force.attach), nchar(packs)) : 
4 arguments passed to .Internal(nchar) which requires 3

会话信息提供以下输出：

> sessionInfo()
R version 3.2.0 (2015-04-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 8 x64 (build 9200)

locale:
[1] LC_COLLATE=German_Germany.1252  LC_CTYPE=German_Germany.1252   
[3] LC_MONETARY=German_Germany.1252 LC_NUMERIC=C                   
[5] LC_TIME=German_Germany.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] mlr_2.8          ParamHelpers_1.7 ggplot2_1.0.1    BBmisc_1.9      

loaded via a namespace (and not attached):
 [1] Rcpp_0.11.5      magrittr_1.5     splines_3.2.0    MASS_7.3-40     
 [5] munsell_0.4.2    xtable_1.8-0     colorspace_1.2-6 R6_2.0.1        
 [9] dplyr_0.4.1      stringr_1.0.0    plyr_1.8.2       tools_3.2.0     
[13] parallel_3.2.0   grid_3.2.0       checkmate_1.7.4  gtable_0.1.2    
[17] DBI_0.3.1        ggvis_0.4.2      htmltools_0.2.6  survival_2.38-1 
[21] assertthat_0.1   leaflet_1.0.0    digest_0.6.8     shiny_0.12.2    
[25] reshape2_1.4.1   htmlwidgets_0.5  mime_0.4         parallelMap_1.3 
[29] stringi_0.4-1    scales_0.3.0     backports_1.0.2  httpuv_1.3.3    
[33] proto_0.3-10

这是 traceback() 的输出：

> lrn = makeLearner("classif.lda")
Error in substr(packs, 1L + (force.load | force.attach), nchar(packs)) : 
  4 arguments passed to .Internal(nchar) which requires 3
> traceback()
8: substr(packs, 1L + (force.load | force.attach), nchar(packs))
7: requirePackages(package, why = paste("learner", id), default.method = "load")
6: makeRLearnerInternal(cl, "classif", package, par.set, par.vals, 
       properties, name, short.name, note)
5: addClasses(makeRLearnerInternal(cl, "classif", package, par.set, 
       par.vals, properties, name, short.name, note), c(cl, "RLearnerClassif"))
4: makeRLearnerClassif(cl = "classif.lda", package = "MASS", par.set = makeParamSet(makeDiscreteLearnerParam(id = "method", 
       default = "moment", values = c("moment", "mle", "mve", "t")), 
       makeNumericLearnerParam(id = "nu", lower = 2, requires = quote(method == 
           "t")), makeNumericLearnerParam(id = "tol", default = 1e-04, 
           lower = 0), makeDiscreteLearnerParam(id = "predict.method", 
           values = c("plug-in", "predictive", "debiased"), default = "plug-in", 
           when = "predict"), makeLogicalLearnerParam(id = "CV", 
           default = FALSE, tunable = FALSE)), properties = c("twoclass", 
       "multiclass", "numerics", "factors", "prob"), name = "Linear Discriminant Analysis", 
       short.name = "lda", note = "Learner parameter `predict.method` maps to `method` in `predict.lda`.")
3: (function () 
   {
       makeRLearnerClassif(cl = "classif.lda", package = "MASS", 
           par.set = makeParamSet(makeDiscreteLearnerParam(id = "method", 
               default = "moment", values = c("moment", "mle", "mve", 
                   "t")), makeNumericLearnerParam(id = "nu", lower = 2, 
               requires = quote(method == "t")), makeNumericLearnerParam(id = "tol", 
               default = 1e-04, lower = 0), makeDiscreteLearnerParam(id = "predict.method", 
               values = c("plug-in", "predictive", "debiased"), 
               default = "plug-in", when = "predict"), makeLogicalLearnerParam(id = "CV", 
               default = FALSE, tunable = FALSE)), properties = c("twoclass", 
               "multiclass", "numerics", "factors", "prob"), name = "Linear Discriminant Analysis", 
           short.name = "lda", note = "Learner parameter `predict.method` maps to `method` in `predict.lda`.")
   })()
2: do.call(constructor, list())
1: makeLearner("classif.lda")

知道为什么会发生此错误（我使用的是 R 版本 3.2.0）吗？

4

0 回答 0