R 重新安排日期

我有三列日期

test <- data.frame(a = as.Date(rep("2008-02-04", 5)),
               b = as.Date(c("2010-01-25",
                             "2012-04-13",
                             "2013-04-04",
                             "2013-09-06",
                             "2014-08-14")),
               c = as.Date(c("2010-01-29",
                             "2012-04-16",
                             NA,
                             "2013-09-19",
                             "2014-08-21"))); test
           a          b          c
1 2008-02-04 2010-01-25 2010-01-29
2 2008-02-04 2012-04-13 2012-04-16
3 2008-02-04 2013-04-04       <NA>
4 2008-02-04 2013-09-06 2013-09-19
5 2008-02-04 2014-08-14 2014-08-21

但对于a行中的第一项，它总是返回NA：

           a          b          c
1       <NA> 2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       <NA>
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21

abc
1        2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21

试试

dplyr:：coalesce

。它返回其参数中的第一个非NA值（按组件）：

test %>% mutate(a = coalesce(lag(c), lag(b), a))

给予：

           a          b          c
1 2008-02-04 2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       <NA>
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21

abc
1 2008-02-04 2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21

感谢使用

coalesce

功能，您是否可以将

coalesce

与向量计算的执行时间进行比较，即

conditionVal=as.Date（ifelse（！is.na（滞后（测试$c））、滞后（测试$c）、滞后（测试$b））；test$a=as.Date（ifelse（is.na（conditionVal），test$a，conditionVal））

@ogiz，如果解决方案令人满意，您可以单击左侧接受它

           a          b          c
1       <NA> 2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       <NA>
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21

test %>% mutate(a = coalesce(lag(c), lag(b), a))

           a          b          c
1 2008-02-04 2010-01-25 2010-01-29
2 2010-01-29 2012-04-13 2012-04-16
3 2012-04-16 2013-04-04       <NA>
4 2013-04-04 2013-09-06 2013-09-19
5 2013-09-19 2014-08-14 2014-08-21