Question

我有一个R数据框，可以从下面的代码中生成

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","",""))

我想做的是根据下面给出的一些条件创建两个新列，分别为admit_start_date和admit_end_date

规则1

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

规则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)

这是我正在尝试的方法，但似乎无济于事

    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)
    )
}

如您所见，我不确定如何为新创建的列检查NA并根据类型列将NAs替换为day_1或day_1 + 5(days)

可以帮忙吗？

我希望我的输出如下所示

Answer 1

在将case_when列转换为实际日期对象之后，我们可以使用"day"分别指定每个条件。

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

数据框中的日期不是“日期”类（class(DF$day_1)），使用mutate_at将其类更改为“日期”，以便可以对其进行数学计算。 starts_with('day')意味着任何名称以"day"开头的列都将转换为“ Date”类。当我们想将相同的函数应用于多个列时，我们使用mutate_at。

case_when是嵌套ifelse语句的替代方法。它们按顺序执行。因此，检查第一个条件，如果满足条件，则不检查其余条件。如果不满足第一个条件，则检查第二个条件，依此类推。因此，此处不需要else。如果不满足任何条件，则返回NA。选中?case_when。

根据R数据帧中的两个条件进行突变

1 个答案: