.searchRpackages<-function(keyword="haha"){
  "Objective: search R packages by a given keyword
  
 Example #1>.searchRpackages       # see this menu
 Example #2>.searchRpackages()     # same 
 Example #3:> .sRp                 # a short-cut
 Example #4  > .sRp('portfolio')
  
                     Package Version
2996        CombinePortfolio     0.4
4615            DOSPortfolio   0.1.0
6455              fPortfolio 4023.84
8233          HierPortfolios   1.0.1
8247     highOrderPortfolios   0.1.1
14182       PolicyPortfolios     0.3
14282              portfolio   0.5-3
14283 portfolio.optimization   1.0-0
14284     PortfolioAnalytics   2.1.0
14285      portfolioBacktest   0.4.1
14286         PortfolioOptim   1.1.1
16253    riskParityPortfolio   0.2.2
16254         RiskPortfolios   2.1.7
16757             rportfolio   0.0.3
  
  Note 1: try different kewyword
  Note 2: rm(.allRpackages)
";.zsearchRpackages(keyword)}
.sRp<<-.searchRpackages

.zsearchRpackages<-function(keyword){

  if(keyword=="haha"){
     print(.sRp) 
  }else{
      if(exists('.allRpackages')==FALSE){
        loc<-"http://cran.us.r-project.org"
        x<-available.packages(repos =loc)
        x2<-data.frame(x[,1:2])
        rownames(x2)<-NULL
        .allRpackages<<-x2
      }
      a<-grep(toupper(keyword),toupper(.allRpackages$Package))
      b<-.allRpackages[a,]
      rownames(b)<-NULL
      print(b)
  }  
}