1. R語言運行效率分析(7)

方法7： 採用 join 語句

1: 自定義函數

Month_name_join<-function(month){
  d_month<-1:12
  d_month_name<-c("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")
  return(left_join(as.data.frame(month),data.frame(d_month,d_month_name),by=c("month"="d_month")))
}
Season_name_join<-function(month){
  d_month<-1:12
  d_season_name<-c("Winter","Winter","Spring","Spring","Spring","Summer","Summer","Summer","Autumn","Autumn","Autumn","Winter")
  return(left_join(as.data.frame(month),data.frame(d_month,d_season_name),by=c("month"="d_month")))
  
}
result_join<-function(month){
  d_month<-1:12
  d_month_name<-c("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")
  d_season_name<-c("Winter","Winter","Spring","Spring","Spring","Summer","Summer","Summer","Autumn","Autumn","Autumn","Winter")
  return(left_join(as.data.frame(month),data.frame(d_month,d_month_name,d_season_name),by=c("month"="d_month")))
}

2: 調用函數進行運算

month<-month_digital(10)
microbenchmark::microbenchmark(Month_name_join(month))
microbenchmark::microbenchmark(Season_name_join(month))
microbenchmark::microbenchmark(result_join(month))

Unit: milliseconds
                   expr      min       lq     mean   median       uq      max
 Month_name_join(month) 1.979469 2.048706 2.467942 2.288968 2.432082 9.385545
 neval
   100
Unit: milliseconds
                    expr    min       lq     mean   median       uq      max
 Season_name_join(month) 1.9838 2.141539 3.546876 2.985441 4.058224 13.25934
 neval
   100
Unit: milliseconds
               expr     min       lq     mean   median      uq      max neval
 result_join(month) 2.24823 2.290183 2.523177 2.323117 2.41993 10.02538   100

(未完！待續……)