将日期列表转换为序列

如何解决将日期列表转换为序列

我正在尝试在日期列表中查找序列，并将其转换为开始日期和结束日期。

我的数据示例如下：

    id  date
1   1   2020-01-01
2   1   2020-01-02
3   1   2020-01-03
4   1   2020-01-06
5   1   2020-01-07
6   2   2020-01-02
7   2   2020-01-03
8   2   2020-01-04
9   2   2020-01-05
10  3   2020-01-04
11  3   2020-01-07

我要创建的是下表：

    id  start date end date
1   1   2020-01-01 2020-01-03
2   1   2020-01-06 2020-01-07
3   2   2020-01-02 2020-01-05
4   3   2020-01-04 2020-01-04
5   3   2020-01-07 2020-01-07

我一直在摆弄diff函数，但是我不能完全按照我想要的方式来工作。

解决方法

public

可复制的数据

DT[,grp := cumsum(date - shift(date,1L,fill = date[1]) > 1),by = id]
DT[,.(start_date = date[1],end_date = date[.N]),by = .(id,grp)][,!"grp"]

#    id start_date   end_date
# 1:  1 2020-01-01 2020-01-03
# 2:  1 2020-01-06 2020-01-07
# 3:  2 2020-01-02 2020-01-05
# 4:  3 2020-01-04 2020-01-04
# 5:  3 2020-01-07 2020-01-07

,

使用by和rle的基本R方法。

res <- do.call(rbind,by(DF,DF$id,function(x) {
  cbind(id=x[1,1],setNames(
    do.call(rbind,Map(function(i,j) data.frame(i,i + j),x[c(0,diff(x[,2])) != 1,2],rle(cumsum(c(0,2])) != 1))$lengths - 1
    )),c("start","end")))
}))
res
#     id      start        end
# 1.1  1 2020-01-01 2020-01-03
# 1.2  1 2020-01-06 2020-01-07
# 2    2 2020-01-02 2020-01-05
# 3.1  3 2020-01-04 2020-01-04
# 3.2  3 2020-01-07 2020-01-07

---

数据：

DF <- structure(list(id = c(1L,2L,3L,3L),date = structure(c(18262,18263,18264,18267,18268,18265,18266,18268),class = "Date")),row.names = c("1","2","3","4","5","6","7","8","9","10","11"),class = "data.frame")

,

一个dplyr选项可能是：

df %>%
 group_by(id) %>%
 mutate(date = as.Date(date,format = "%Y-%m-%d")) %>%
 group_by(id,grp = cumsum(c(0,!diff(date) %in% 0:1))) %>%
 summarise(start_date = min(date),end_date = max(date))

     id   grp start_date end_date  
  <int> <dbl> <date>     <date>    
1     1     0 2020-01-01 2020-01-03
2     1     1 2020-01-06 2020-01-07
3     2     0 2020-01-02 2020-01-05
4     3     0 2020-01-04 2020-01-04
5     3     1 2020-01-07 2020-01-07

,

单线（但与其他答案没有什么不同）

library(data.table)
dt <- data.table(
  id = c(1,1,2,3,3),date = lubridate::ymd('2020-01-01')+c(0:2,5,6,1:4,6))

# calculate
dt[,.(start = date[c(T,x <- diff(date) != 1)],end = date[c(x,T)]),id]

#>    id      start        end
#> 1:  1 2020-01-01 2020-01-03
#> 2:  1 2020-01-06 2020-01-07
#> 3:  2 2020-01-02 2020-01-05
#> 4:  3 2020-01-04 2020-01-04
#> 5:  3 2020-01-07 2020-01-07