比較連續的列單元格值並替換其他列值

Question

我有一個下面顯示的數據框，在這里我要比較lse列中的連續值。 如果lse 0的值后跟1 ，我想將lse的END_DATE的值設為0作為NA輸入：

END_DATE      lse   
2016-01-20     0  
2015-08-16     1

預期產量：

  END_DATE     lse   
        NA     0  
2015-08-16     1

我已經嘗試過下面的代碼，但是它不起作用並且不會引發任何錯誤。

for (i in length(loan_test1$lse)){
  if (length(loan_test1$lse) == 0 & length(loan_test1$lse)+1 == 1) {
    loan_test1$END_DATE[i] <- "NA"
  }
}

誰能幫我 ？

Answer 1

library(lubridate)
library(tidyverse)
df <- data.frame(END_DATE = seq.Date(from = (today()-99),to = today(),by=1),lse = sample(c(0,1), 100, replace = TRUE))

df <- df %>% mutate(leadlse = lead(lse))

condition <- df$lse == 0 & df$leadlse ==1

df$END_DATE[condition] = NA

df <- df %>% select(-leadlse)
df

或更簡單地說：

df <- data.frame(END_DATE = seq.Date(from = (today()-99),to = today(),by=1),lse = sample(c(0,1), 100, replace = TRUE))

df$END_DATE[(df$lse == 0 & lead(df$lse) == 1)] <- NA