r - 在 R 中标记唯一值

Question

我的数据看起来像:

data <- matrix(c("1","install","2015-10-23 14:07:20.000000",
                 "2","install","2015-10-23 14:08:20.000000",
                 "3","install","2015-10-23 14:07:25.000000",
                 "3","sale","2015-10-23 14:08:20.000000",
                 "4","install","2015-10-23 14:07:20.000000",
                 "4","sale","2015-10-23 14:09:20.000000",
                 "4","sale","2015-10-23 14:11:20.000000"),
               ncol=3, byrow=TRUE)
colnames(data) <- c("id","event","time")

我想添加第四列，称为标签，其中我在某些值上相应地标记每一行。在这种情况下:

如果 id 是唯一的，则为“0”标签

如果 id 不是唯一的并且关联了 1 个销售，则为“1”标签

如果 id 不是唯一的并且关联了 2 个销售，则为“2”标签

依此类推，最多为 n 次销售。

它应该最终看起来像:

data1 <- matrix(c("1","install","2015-10-23 14:07:20.000000","0",
                  "2","install","2015-10-23 14:08:20.000000","0",
                  "3","install","2015-10-23 14:07:25.000000","1",
                  "3","sale","2015-10-23 14:08:20.000000","1",
                  "4","install","2015-10-23 14:07:20.000000","2",
                  "4","sale","2015-10-23 14:09:20.000000","2",
                  "4","sale","2015-10-23 14:11:20.000000","2"),
                 ncol=4, byrow=TRUE)

我不清楚在 R 中根据条件创建“标签”的最佳方法是什么......也许 dplyr::mutate ?

Answer 1

更新以反射(reflect)“等等最多 n 次销售。”-要求。

dplyr 选项可以是:

library(dplyr)
data <- as.data.frame(data)
data %>% 
  group_by(id) %>% 
  mutate(label = if(n() == 1) 0 else as.numeric(sum(event == "sale")))

#Source: local data frame [7 x 4]
#Groups: id [4]
#
#      id   event                       time label
#  (fctr)  (fctr)                     (fctr) (dbl)
#1      1 install 2015-10-23 14:07:20.000000     0
#2      2 install 2015-10-23 14:08:20.000000     0
#3      3 install 2015-10-23 14:07:25.000000     1
#4      3    sale 2015-10-23 14:08:20.000000     1
#5      4 install 2015-10-23 14:07:20.000000     2
#6      4    sale 2015-10-23 14:09:20.000000     2
#7      4    sale 2015-10-23 14:11:20.000000     2

data.table 等价物将是:

library(data.table)
data <- as.data.table(data)  # or setDT(data) if it's already a data.frame
data[, label := if(.N == 1) 0 else as.numeric(sum(event == "sale")), by=id]