基於 R 數據幀中的兩個條件進行變異

Question

我有一個 R 數據框，可以從下面的代碼生成

DF <- data.frame("Person_id" = c(1,1,1,1,2,2,2,2,3,3), "Type" = c("IN","OUT","IN","ANC","IN","OUT","IN","ANC","EM","ANC"), "Name" = c("Nara","Nara","Nara","Nara","Dora","Dora","Dora","Dora","Sara","Sara"),"day_1" = c("21/1/2002","21/4/2002","21/6/2002","21/9/2002","28/1/2012","28/4/2012","28/6/2012","28/9/2012","30/06/2004","30/06/2005"),"day_2" = c("23/1/2002","21/4/2002","","","30/1/2012","28/4/2012","","28/9/2012","",""))

我想要做的是根據下面給出的幾個條件創建兩個新列作為admit_start_date和admit_end_date

規則1

  admit_start_date = day_1
  admit_end_date   = day_2 (sometimes day_2 can be NA. So refer Rule 2 below)

規則 2

   if day_2 is (null or blank or na) and Type is (Out or ANC or EM) then 
         admit_end_date = day_1 
   else (if Type is IN)
         admit_end_date = day_1 + 5 (days)

這是我正在嘗試但似乎沒有幫助

    transform_dates = function(DF){  # this function is to create 'date' columns  
  DF %>% 
    mutate(admit_start_date = day_1) %>% 
    mutate(admit_end_date = day_2) %>%
    admit_end_date = if_else(((Type == 'Out' & admit_end_date.isna() ==True|Type == 'ANC' & admit_end_date.isna() ==True|Type == 'EM' & admit_end_date.isna() ==True),day_1,day_1 + 5)
    )
}  

正如你所看到的，我不知道如何檢查NA為新創建的列，並取代那些NAs與day_1或day_1 + 5(days)基於類型列。

你能幫忙嗎？

我希望我的輸出如下所示

Answer 1

在將"day"列轉換為實際日期對象后，我們可以使用case_when分別指定每個條件。

library(dplyr)

DF %>%
  mutate_at(vars(starts_with('day')), as.Date, "%d/%m/%Y") %>%
  mutate(admit_start_date = day_1, 
         admit_end_date = case_when(
         !is.na(day_2) ~day_2,
         is.na(day_2) & Type %in% c('OUT', 'ANC', 'EM') ~ day_1, 
         Type == 'IN' ~ day_1 + 5))


#  Person_id Type Name      day_1      day_2 admit_start_date admit_end_date
#1          1   IN Nara 2002-01-21 2002-01-23       2002-01-21     2002-01-23
#2          1  OUT Nara 2002-04-21 2002-04-21       2002-04-21     2002-04-21
#3          1   IN Nara 2002-06-21       <NA>       2002-06-21     2002-06-26
#4          1  ANC Nara 2002-09-21       <NA>       2002-09-21     2002-09-21
#5          2   IN Dora 2012-01-28 2012-01-30       2012-01-28     2012-01-30
#6          2  OUT Dora 2012-04-28 2012-04-28       2012-04-28     2012-04-28
#7          2   IN Dora 2012-06-28       <NA>       2012-06-28     2012-07-03
#8          2  ANC Dora 2012-09-28 2012-09-28       2012-09-28     2012-09-28
#9          3   EM Sara 2004-06-30       <NA>       2004-06-30     2004-06-30
#10         3  ANC Sara 2005-06-30       <NA>       2005-06-30     2005-06-30

數據class(DF$day_1)日期不是“Date” class(DF$day_1) （ class(DF$day_1) ），使用mutate_at我們將它們的類更改為“Date”，以便我們可以對其進行數學計算。 starts_with('day')意味着名稱以"day"開頭的任何列都將轉換為“Date”類。 當我們想將相同的函數應用於多個列時，我們使用mutate_at 。

case_when是嵌套ifelse語句的替代方法。 它們按順序執行。 因此檢查第一個條件，如果滿足條件，則不檢查其余條件。 如果不滿足第一個條件，則檢查第二個條件，依此類推。 因此，這里不需要else 。 如果不滿足任何條件，則返回NA 。 檢查?case_when 。