R使用dayeries作为字符串数据制作索引？答案

【问题标题】：R make index with dayseries as string data?R使用dayeries作为字符串数据制作索引？
【发布时间】：2013-10-23 08:48:00
【问题描述】：

我有一个具有以下特征的字符串数据
c = ("19790102", "19790103", "19790104", "19790105",...).

现在我想为不同的季节（夏、秋、冬、春）做一个索引。我只用了一个月（例如九月）就做到了：

ind_september=which(as.numeric(substr(dayserie[],5,6))==9)

但我不知道如何用几个月的时间来获得季节索引。

有人有想法吗？

【问题讨论】：

也许你在这里找到答案：link

标签： string r indices

【解决方案1】：

使用 Find which season a particular date belongs to ，我巧妙地更改了函数以添加格式参数：

getSeason <- function(DATES,frmt = "%Y%m%d") {
  WS <- as.POSIXct("2012-12-21", format = "%Y-%m-%d") # Winter 
  SE <- as.POSIXct("2012-3-21",  format = "%Y-%m-%d") # Spring 
  SS <- as.POSIXct("2012-6-21",  format = "%Y-%m-%d") # Summer 
  FE <- as.POSIXct("2012-9-21",  format = "%Y-%m-%d") # Autumn 

  # Convert dates from any year to 2012 dates
  d <- strftime(as.POSIXct(DATES, format=frmt),
                format='2012-%m-%d')

  ifelse (d >= WS | d < SE, "Winter",
          ifelse (d >= SE & d < SS, "Spring",
                  ifelse (d >= SS & d < FE, "Summer", "Fall")))
}

dayserie <- c("19790102", "19790103", "19790104", "19790105")
getSeason(dayserie,'%Y%m%d')

"Winter" "Winter" "Winter" "Winter"

【讨论】：

【解决方案2】：

您也可以查看seas 包。

library(seas)

x <- c("19790304", "19790603", "19790903",  "19791205")

x2 <- as.Date(x, format = "%Y%m%d")

# width = "JFM": annual quarterly divisions: JFM, AMJ, JAS, OND
x3 <- mkseas(x2, width = "JFM")
x3
# [1] JFM AMJ JAS OND

# if you wish to rename factor levels
x4 <- factor(x3, labels = c("winter", "spring", "summer", "autumn"))
x4
# [1] winter spring summer autumn

# alternative division
# width = "DJF": meteorological quarterly divisions: DJF, MAM, JJA, SON
x3 <- mkseas(x2, width = "DJF")
x3
# [1] MAM JJA SON DJF

x4 <- factor(x3, labels = c("winter", "spring", "summer", "autumn"))
x4
# [1] spring summer autumn winter

【讨论】：