R语言学习笔记7-程序结构篇

- Basic
    - u<-matrix(c(1,2,3,1,2,4),nrow=3)
    - v<-matrix(c(8,12,20,15,10,2),nrow=3)
    - for (m in c("u","v")) {
        - z<-get(m)
        - print(lm(z[,2]~z[,1]))
    - }
    - y<-if(x==2) x else x+1
    - x%/%y    # integer divide
    - x%%y    # mod
    - x&y    # vector and
    - x|y    # vector or
    - |x    # not
    - oddcount<-function(x) {
        - k<-0
        - k    # as return val
    - }
    - g<-function() {
        - t<-function(x) return(x^2)
        - return(t)
    - }
    - ls()    # show current environment variable
    - x<-c(13,5,12)
    - sort(x)    # 5 12 13
    - x    # not changed x
        - 13 5 12
    - x<-sort(x)    # 5 12 13
    - oddsevens<-function(v) {
        - odds<-which(v%%2==1)
        - evens<-which(v%%2==1)
        - list(o=odds,e=evens)    # return multiple values
    - }
    - # global variable
    - f<-function() {
        - x<<-...
        - y<<-...
    - }
    - x<-...
    - y<-...
    - f()    # x,y are changed in f
    - ...<-x
    - ...<-y    # use new x,y
    - # clojure
    - counter<-function() {
        - ctr<-0
        - f<-function() {
            - ctr<<-ctr+1
            - cat("sentence",ctr,"\n")
        - }
        - return(f)
    - }
    - c1<-counter()
    - c2<-counter()
    - c1()    # ctr=1
    - c1()    # ctr=2
    - c2()    # ctr=1
    - c2()    # ctr=2
    - # recursion
    - quicksort<-function(x) {
        - if (length(x)<=1) return(x)    # end condition
        - pivot<-x[1]
        - therest<-x[-1]
        - sv1<-therest[therest<pivot]
        - sv2<-therest[therest>=pivot]
        - sv1<-quicksort(sv1)
        - sv2<-quicksort(sv2)
        - return(c(sv1,pivot,sv2))
    - }
    - "%a2b%"<-function(a,b) return(a+2*b)    # custom operator
    - 3 %a2b% 5
    - y<-apply(z,1,function(x) x/c(2,8))    # anonymous function