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"