如何使用data.frame重写我的dataframe转换

我有一个数据帧：

ID       value
1      he following object is masked from ‘package:purrr’. R is free software and comes with ABSOLUTELY NO WARRANTY
2      Attaching package: ‘magrittr’. Natural language support but running in an English locale
2      Attaching package: ‘DT’. Natural language support but running in an English locale
2      Attaching package: ‘anytime’. Natural language support but running in an English locale
3      package ‘ggplot2’ was built under R version 3.6.2. Type 'contributors()' for more information
4      Warning messages: type 'demo()' for some demos, 'help()' for on-line help
4      Warning messages: 'help.start()' for an HTML browser interface to help

如何创建它：

ID <- c(1,2,2,2,3,4,4)
value <- c("he following object is masked from ‘package:purrr’. R is free software and comes with ABSOLUTELY NO WARRANTY",
           "Attaching package: ‘magrittr’. Natural language support but running in an English locale",
           "Attaching package: ‘DT’. Natural language support but running in an English locale",
           "Attaching package: ‘anytime’. Natural language support but running in an English locale",
           "package ‘ggplot2’ was built under R version 3.6.2. Type 'contributors()' for more information",
           "Warning messages:type 'demo()' for some demos, 'help()' for on-line help",
           "Warning messages:'help.start()' for an HTML browser interface to help")



df <- data.table(ID, value)

以及它所期望的输出。如您所见，我创建了新的列模式，并根据它对数据表进行了分组。我还添加了带有模式示例的列示例

如何使用data.table重写此转换？我希望使用data.table的函数，而不是使用mutate和其他函数。但是我不擅长。我试过了，但我不知道下一步该怎么办：

df_patterns <- df[, c("pattern", "id_type") := list(
  pattern = coalesce(stringr::str_extract(pattern= stringr::str_extract(value, "\\S+\\s+\\S+\\s+\\S+"), "^Attaching package:|Warning messages:"),pattern= stringr::str_extract(value, "\\S+\\s+\\S+\\s+\\S+")),
  case_when(ID %in% c(1, 5) ~ "extra_type")), by = ID, pattern]

---

df_patterns删除除
数据之外的所有依赖项。表
以下内容应与您的预期输出相匹配（当然，在不设置种子的情况下会有所不同）：

df_patterns您能解释一下预期的输出吗？@zx8754我添加了一些说明找不到函数“fcase”。我在data.table包中没有该函数，我将列id\u类型添加到了所需的结果中。我昨天晚上忘了beginning@french_fries您有一个旧版本的
data.table
。要安装最新版本，请使用
install.packages（'data.table'）
。已将解决方案更新为包含
id\u type
。
ID            pattern                  example                                                                                                               id_type                               
1      he following object        he following object is masked from ‘package:purrr’. R is free software and comes with ABSOLUTELY NO WARRANTY             extra_type

2      Attaching package:         Attaching package: ‘anytime’. Natural language support but running in an English locale                                     NA

3      package ‘ggplot2’ was      package ‘ggplot2’ was built under R version 3.6.2. Type 'contributors()' for more information                               NA

4      Warning messages:          Warning messages:'help.start()' for an HTML browser interface to help                                                       NA

df_patterns <- df[, c("pattern", "id_type") := list(
  pattern = coalesce(stringr::str_extract(pattern= stringr::str_extract(value, "\\S+\\s+\\S+\\s+\\S+"), "^Attaching package:|Warning messages:"),pattern= stringr::str_extract(value, "\\S+\\s+\\S+\\s+\\S+")),
  case_when(ID %in% c(1, 5) ~ "extra_type")), by = ID, pattern]

df_patterns <- 
  copy(df)[, pattern := fcase(
               startsWith(value, "Attaching package:"), "Attaching package:",
               startsWith(value, "Warning messages:"), "Warning messages:",
               rep(TRUE, nrow(df)), sub("((\\S+\\s+){2}\\S+).+", "\\1", value)
             )][, 
                .(
                  example = sample(value, 1), 
                  id_type = fifelse(ID %in% c(1,5),  "extra_type", NA_character_)
                ), 
                by = .(ID, pattern)]


   ID               pattern                                                                                                      example    id_type
1:  1   he following object he following object is masked from ‘package:purrr’. R is free software and comes with ABSOLUTELY NO WARRANTY extra_type
2:  2    Attaching package:                           Attaching package: ‘DT’. Natural language support but running in an English locale       <NA>
3:  3 package ‘ggplot2’ was                package ‘ggplot2’ was built under R version 3.6.2. Type 'contributors()' for more information       <NA>
4:  4     Warning messages:                                     Warning messages:type 'demo()' for some demos, 'help()' for on-line help       <NA>