使用R中的lubridate从日期确定季节 [英] Determine season from Date using lubridate in R

问题描述

我有一个很大的数据集，其中的DateTime列包含POSIXct-Values.我需要根据DateTime列确定季节(冬季-夏季).我创建了一个在小型数据集上可以正常运行的函数，但是在大型数据集上使用时会崩溃.有人可以看到我的错误吗?

I have a very big dataset with a DateTime Column containing POSIXct-Values. I need to determine the season (Winter - Summer) based on the DateTime column. I've created a function which works fine on a small dataset, but crashes when I use it on the large one. Can anybody see my mistake?

我已经创建了4个函数:

I've created 4 functions:

• 3个子功能，这样我就可以进行逻辑比较和选择 使用* apply函数
• 1个确定季节的功能

• 3 subfunctions so that I can do logical comparisons and selection using *apply functions
• 1 function to determine the season

以下是功能:

require(lubridate)

# function for logical comparison (to be used in *apply)
greaterOrEqual <- function(x,y){
  ifelse(x >= y,T,F)
}

# function for logical comparison (to be used in *apply)
less <- function(x,y){
  ifelse(x < y,T,F)
}

# function for logical comparison (to be used in *apply)
selFromLogic <- function(VecLogic,VecValue){
  VecValue[VecLogic]
}

# Main Function to determine the season
getTwoSeasons <- function(input.date) {
  Winter1Start <- as.POSIXct("2000-01-01 00:00:00", tz = "UTC")
  Winter1End <- as.POSIXct("2000-04-15 23:59:59", tz = "UTC")

  SummerStart <- Winter1End + 1
  SummerEnd <- as.POSIXct("2000-10-15 23:59:59", tz = "UTC")

  Winter2Start <- SummerEnd + 1
  Winter2End <- as.POSIXct("2000-12-31 00:00:00", tz = "UTC")

  year(input.date) <- year(Winter1Start)
  attr(input.date, "tzone") <- attr(Winter1Start, "tzone")

  SeasonStart <- c(Winter1Start,SummerStart,Winter2Start)
  SeasonsEnd <- c(Winter1End,SummerEnd,Winter2End)
  Season_names <- as.factor(c("WinterHalfYear","SummerHalfYear","WinterHalfYear"))

  Season_select <- sapply(SeasonStart, greaterOrEqual, x = input.date) & sapply(SeasonsEnd, less, x = input.date)
  Season_return <- apply(Season_select,MARGIN = 1,selFromLogic,VecValue = Season_names)

  return(Season_return)
}

这是测试功能的一种方法:

And here's a way to test the function:

dates <- Sys.time() + seq(0,10000,10)
getTwoSeasons(dates)

感谢您的帮助，这让我发疯了！

I would be thankful for any help, this is driving me crazy!

推荐答案

我将@Lars Arne Jordanger更为优雅的方法打包为一个函数:

I packaged @Lars Arne Jordanger's much more elegant approach into a function:

getTwoSeasons <- function(input.date){
  numeric.date <- 100*month(input.date)+day(input.date)
  ## input Seasons upper limits in the form MMDD in the "break =" option:
  cuts <- base::cut(numeric.date, breaks = c(0,415,1015,1231)) 
  # rename the resulting groups (could've been done within cut(...levels=) if "Winter" wasn't double
  levels(cuts) <- c("Winter", "Summer","Winter")
  return(cuts)
}

在一些示例数据上对其进行测试似乎可以正常工作:

Testing it on some sample data seems to work fine:

getTwoSeasons(as.POSIXct("2016-01-01 12:00:00")+(0:365)*(60*60*24))

这篇关于使用R中的lubridate从日期确定季节的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！