使用日期时间列投射数据框

Question

我已经用 R 构建了一个数据框，从我的电子邮件中读取了一些事件。 基本上，最终dataframe的结构如下：

'data.frame':   74 obs. of  7 variables:
 $ process_name : Factor w/ 2 levels : 1 1 1 1 2 2 2 2 2 2 ...
 $ job_code : chr  "TRB1619825404" "TRB1619825404" "TRB1619825404" "TRB1619825404" ...
 $ phase           : Factor w/ 7 levels ,..: 4 4 6 6 4 5 7 1 3 2 ...
 $ stage          : Factor w/ 2 levels "End","Start": 2 1 2 1 2 1 2 2 2 2 ...
 $ date          : POSIXct, format: "2021-04-30 23:30:04" "2021-05-01 01:57:26" "2021-05-01 01:57:26" "2021-05-01 02:25:26" ...
 $ execution_date: Date, format: "2021-04-30" "2021-05-01" "2021-05-01" "2021-05-01" ...
 $ execution_time : 'hms' num  23:30:04 01:57:26 01:57:26 02:25:26 ...
  ..- attr(*, "units")= chr "secs"

每个事件的开始和结束都有相关的日期和时间。 我想要做的（为了计算事件的持续时间）是将数据帧转换成这样的：

'data.frame'
 $ process_name
 $ job_code
 $ phase
 $ start_date
 $ end_date
 $ duration         

我尝试使用 dcast，但它使用默认聚合函数，我只想重塑数据框。 有什么想法吗？

Answer 1

首先，我猜你的数据是这样的：

dat <- structure(list(process_name = structure(c(1L, 1L, 1L, 1L), .Label = c("L01", "L02"), class = "factor"), job_code = c("TRB1619825404", "TRB1619825404", "TRB1619825404", "TRB1619825404"), phase = structure(c(3L, 3L, 5L, 5L), .Label = c("L02", "L03", "L04", "L05", "L06", "L07"), class = "factor"), stage = structure(c(2L, 1L, 2L, 1L), .Label = c("End", "Start" ), class = "factor"), date = structure(c(1619825404, 1619834246, 1619834246, 1619835926), class = c("POSIXct", "POSIXt"), tzone = "UTC"), execution_date = structure(c(18747, 18748, 18748, 18748), class = "Date"), execution_time = c("30:04", "01:57:26", "01:57:26", "02:25:26" )), row.names = c(NA, 4L), class = "data.frame")

（如果没有，请以我们可以使用的方式提供您的数据。）

从这里开始：

out <- reshape2::dcast(dat[,1:5], process_name + job_code + phase ~ stage, value.var = "date")
out[,c("End","Start")] <- lapply(out[,c("End","Start")], as.POSIXct, origin = "1970-01-01", tz = "UTC")
out$duration <- difftime(out$End, out$Start, units = "mins")
out
#   process_name      job_code phase                 End               Start      duration
# 1          L01 TRB1619825404   L04 2021-05-01 01:57:26 2021-04-30 23:30:04 147.3667 mins
# 2          L01 TRB1619825404   L06 2021-05-01 02:25:26 2021-05-01 01:57:26  28.0000 mins

我不得不重新as.POSIXct 它，因为dcast 将它们转换为numeric（不知道如何解决这个问题）。