其中有不少是在重复造轮子

pdb <- tools::CRAN_package_db()

grep(x = pdb$Package, pattern="*2$",value=T)

  [1] "ABCp2"                 "abf2"                  "ANN2"                 
  [4] "argon2"                "ARTP2"                 "aster2"               
  [7] "BDP2"                  "BEQI2"                 "BHH2"                 
 [10] "biomod2"               "Bolstad2"              "BradleyTerry2"        
 [13] "brglm2"                "bridger2"              "c212"                 
 [16] "CB2"                   "cld2"                  "CLONETv2"             
 [19] "condvis2"              "cosinor2"              "cvq2"                 
 [22] "DALEX2"                "Digiroo2"              "DMwR2"                
 [25] "DTRlearn2"             "dttr2"                 "EffectStars2"         
 [28] "emme2"                 "empiricalFDR.DESeq2"   "emplik2"              
 [31] "estudy2"               "EWOC2"                 "exact2x2"             
 [34] "fastR2"                "fpp2"                  "Frames2"              
 [37] "FrF2"                  "FuzzyNumbers.Ext.2"    "GB2"                  
 [40] "ggplot2"               "glm2"                  "GMDH2"                
 [43] "gprofiler2"            "GREP2"                 "grImport2"            
 [46] "groupdata2"            "gWidgets2"             "gWidgets2RGtk2"       
 [49] "gWidgetsRGtk2"         "HSAUR2"                "hyper2"               
 [52] "IC2"                   "isa2"                  "itertools2"           
 [55] "kinship2"              "lasso2"                "lavaSearch2"          
 [58] "lmodel2"               "longRPart2"            "MCI2"                 
 [61] "mlica2"                "mmm2"                  "momentchi2"           
 [64] "mudata2"               "nls2"                  "nonnest2"             
 [67] "norm2"                 "NSO1212"               "outbreaker2"          
 [70] "PASWR2"                "PGM2"                  "phyext2"              
 [73] "pwr2"                  "qicharts2"             "qwraps2"              
 [76] "r2d2"                  "RcmdrPlugin.KMggplot2" "RDota2"               
 [79] "rdrop2"                "rematch2"              "reshape2"             
 [82] "Rfast2"                "rgeopat2"              "RGtk2"                
 [85] "RH2"                   "ri2"                   "RI2by2"               
 [88] "RM2"                   "ROC632"                "roxygen2"             
 [91] "rr2"                   "rstpm2"                "rzeit2"               
 [94] "s2"                    "sae2"                  "SCORER2"              
 [97] "sharpr2"               "shinybootstrap2"       "Sleuth2"              
[100] "splines2"              "support.BWS2"          "survAWKMT2"           
[103] "survRM2"               "tcltk2"                "TITAN2"               
[106] "tsdisagg2"             "udunits2"              "UncerIn2"             
[109] "UtilityFrailtyPH12"    "wordcloud2"            "wpp2012"              
[112] "WRS2"                  "x12"                   "xml2"                 
[115] "xmlrpc2"