r - 如何对由其他列定义的组内的列中的值进行索引？

Question

我有一个数据框:

dput(df)
structure(list(ID = c("A1", "A1", "A1", "A1", "A1", "A1", "B2",
"B2", "B2", "B2", "B2", "B2", "B2", "B2", "B2", "B2"), operation = c("open",
"open", "close", "", "open", "close", "", "open", "open", "open",
"close", "upload", "open", "close", "open", "close")), class = "data.frame", row.names = c(NA,
-16L))

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

我是这样做的:

rank <- df$operation == "close" & !is.na(df$operation)
df$index <- cumsum(c(1, rank[-length(rank)]))
df$index[!df$operation %in% c("open", "close")] <- NA

现在我想在每个 ID 中建立这个索引。所以对于每个 ID 索引从头开始。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         1
B2       open         1
B2       open         1
B2       close        1
B2       upload
B2       open         2
B2       close        2
B2       open         3
B2       close        3

我怎么能那样做？

Answer 1

这是使用 data.table 的一种方法:

library(data.table)

setDT(df)
df[!is.na(index), index := rleid(index), by = .(ID)]
df
#     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     1
#  9: B2      open     1
# 10: B2      open     1
# 11: B2     close     1
# 12: B2    upload    NA
# 13: B2      open     2
# 14: B2     close     2
# 15: B2      open     3
# 16: B2     close     3

有名为 dt 或 df 的内置 R 函数。虽然 R 可以区分变量和函数，但最好使用其他名称。