如何将每日 Value 汇总限制为月度和年度总计？

1 回答

• 0

  如果使用 plyr 是一个选项，这是一种方法 . 您必须将动物园对象 stn 设置为数据框 .

  rain <- data.frame(date=c("1987-01-01", "1987-01-02", "1987-01-03", "1988-10-01", "1988-11-02", "1988-11-01"), 
                pcp=c(2, 0.6, 1, 2.7, 1.1, 1.3)
             )
  
  rain$Year <- 1900+as.POSIXlt(rain$date)$year
  rain$Month <-1+as.POSIXlt(rain$date)$mon
  rain$Day <-as.POSIXlt(rain$date)$mday
  
  annualAgg <- function(df) {
     if(length(unique(df$Month))<10) return(NULL) #aggregate only if <10 months in that year
    mean(df$pcp)
  }
  
  monthlyRainAgg <- function(df) {
    if(length(unique(df$Day))<20) return(NULL) #aggregate monthly only if <20 days in that month
    mean(df$pcp)
  }
  
  library(plyr)
  ## Call the functions above using ddply
  # ddply sends the functions thinly sliced df's
  monthly.agg.df <- ddply(rain, .(Year, Month), monthlyRainAgg)
  monthly.agg.df
  
  annual.agg <-  ddply(rain, .(Year), annualAgg)
  annual.agg
  

  回复于 2024-04-28T13:07:37+08:00