r:在特定条件下，将日期添加到日期变量中

Question

我试图在to变量中添加一天，但前提是from没有丢失：

df <- data.frame(from = c("2020-01-01", "2020-02-01", ""),
to   = c("2020-01-05", "2020-02-20", "2020-03-04"))
df <- df %>% mutate(
from = as.Date(from),
to = as.Date(to),
to = ifelse(!is.na(from), to + 1, to)
)
df

显然，这不起作用：(.有人能告诉我怎么做吗？

Answer 1

试试这个。函数ifelse()用于将日期转换为数字。相反，您可以使用dplyr中的if_else()。这里的代码：

#Data
df <- data.frame(from = c("2020-01-01", "2020-02-01", ""),
to   = c("2020-01-05", "2020-02-20", "2020-03-04"))
#Variables
df <- df %>% mutate(
from = as.Date(from),
to = as.Date(to),
to = if_else(!is.na(from), to + 1, to)
)
#Output
df

输出：

df
from         to
1 2020-01-01 2020-01-06
2 2020-02-01 2020-02-21
3       <NA> 2020-03-04

Answer 2

我们也可以进行

library(lubridate)
library(dplyr)
df %>%
mutate(across(everything(), ymd), 
to = case_when(!is.na(from)~ to+1, TRUE ~ to))

-输出

#       from         to
#1 2020-01-01 2020-01-06
#2 2020-02-01 2020-02-21
#3       <NA> 2020-03-04