[英]Calculate days between sequential dates in single column
我有以下數據框,其中包含日期列和評估列:
dates<-c("2015-01-02","2015-01-10","2016-01-15")
assessments<-c('1','2','3')
dates_dataframe = data.frame(dates, assessments)
dates_dataframe$dates<-as.Date(dates_dataframe$dates)
我想在此數據框中創建另一列,其中包含一次評估與下一次評估之間的天數。
我將如何去做呢?
您可以使用diff
來做到這一點:
dates_dataframe$days = c(0, diff(dates_dataframe$dates))
dates_dataframe$days2 = c(diff(dates_dataframe$dates), 0)
或使用NA:
dates_dataframe$days3 = c(NA, diff(dates_dataframe$dates))
dates_dataframe$days4 = c(diff(dates_dataframe$dates), NA_character_)
結果:
> dates_dataframe
dates assessments days days2 days3 days4
1 2015-01-02 1 0 8 days NA 8 days
2 2015-01-10 2 8 370 days 8 370 days
3 2016-01-15 3 370 0 days 370 NA days
另一種方法是使用shift
功能:
# create data
dates<-c("2015-01-02","2015-01-10","2016-01-15")
assessments<-c('1','2','3')
df <- data.table(dates, assessments)
# convert to date format
df[, dates := as.Date(dates)]
# shift
df[, next_dates := shift(dates, 1)]
# get difference
df[, difference := abs(next_dates - dates)]
dates assessments next_dates difference
1: 2015-01-02 1 <NA> NA days
2: 2015-01-10 2 2015-01-02 8 days
3: 2016-01-15 3 2015-01-10 370 days
我認為您應該使用useR的答案,但這是另一個答案:
dates<-c("2015-01-02","2015-01-10","2016-01-15")
assessments<-c('1','2','3')
dates_dataframe <- cbind.data.frame(dates, assessments)
dates_dataframe$dates <- as.Date(dates_dataframe$dates)
dates_dataframe$dates_shift = shift(dates_dataframe$dates,1)
dates_dataframe$days <- (dates_dataframe$dates - dates_dataframe$dates_shift)
dates assessments dates_shift days
1 2015-01-02 1 <NA> NA days
2 2015-01-10 2 2015-01-02 8 days
3 2016-01-15 3 2015-01-10 370 days
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.