r - 如何为其他列中的一组值创建索引列

Question

我有一个数据框:

ID      operation
A1       open
A1       open
A1       close
A1       
A1       open
A1       close
B2      
B2       open
B2       open
B2       open
B2       close
B2       upload
B2       open
B2       close
B2       open
B2       close

我想在列操作中为每个“打开”和“关闭”包添加索引。所以对于 open 和 close 之间的每一行都必须具有相同的索引。所以想要的结果是:

ID      operation    index
A1       open         1
A1       open         1
A1       close        1
A1       
A1       open         2
A1       close        2
B2      
B2       open         3
B2       open         3
B2       open         3
B2       close        3
B2       upload
B2       open         4
B2       close        4
B2       open         5
B2       close        5

我怎么能那样做？哪些功能可用于这些以及如何应用它？最好使用 data.table

Answer 1

这是在 data.table 中执行此操作的方法:

dt[, index := .GRP, by = .(rev(cumsum(rev(operation) == 'close')))]
dt[, index := ifelse(cumsum(operation == 'open') > 0, index, NA), by = .(ID, index)]
dt
#     ID operation index
#  1: A1      open     1
#  2: A1      open     1
#  3: A1     close     1
#  4: A1              NA
#  5: A1      open     2
#  6: A1     close     2
#  7: B2              NA
#  8: B2      open     3
#  9: B2      open     3
# 10: B2      open     3
# 11: B2     close     3
# 12: B2    upload    NA
# 13: B2      open     4
# 14: B2     close     4
# 15: B2      open     5
# 16: B2     close     5

由于 cumsum的两条路径, 如果操作不在 c('open', 'close') 中， 它会:

如果它在 open 之间，则获得正确的索引和 close ;

获取 NA如果在 close 之间和 open .