r - 从文件名中提取字符串并使用 mutate 创建新列

Question

我有一个包含两列的数据框。第二列是文件名。

df  <- data.frame(paragraph = "Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.",
             filename = "./data/RevCon_2015_C1_Austria_05_06.txt", stringsAsFactors = FALSE)

如何从第二列中提取某些字符串(使用 stringr)并将它们添加(使用 dplyr::mutate)作为附加变量( session 、年份、国家/地区)等)，这样我得到以下结果:

df2  <- data.frame(paragraph = "Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.",
              filename = "./data/RevCon_2015_C1_Austria_05_06.txt", conference = "RevCon", year = "2015", country= "Austria", date = "06.05.2015", stringsAsFactors = FALSE)

Answer 1

我们可以使用 tidyr::separate 执行以下操作:

library(tidyverse);
df %>%
    mutate(tmp = gsub("(\\./data/|\\.txt)", "", filename)) %>%
    separate(
        tmp,
        into = c("conference", "year", "ignored", "country", "month", "day")) %>%
    mutate(date = paste(day, month, year, sep = "/")) %>%
    select(-ignored, -month, -day)
#          paragraph                                filename conference year
#1 Lorem ipsum [...] ./data/RevCon_2015_C1_Austria_05_06.txt     RevCon 2015
#  country        date
#1 Austria  06/05/2015

请注意，这假设文件名遵循以下模式:./data/{conference}_{year}_{ignored}_{country}_{month}_{日}.txt

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示例数据

df  <- data.frame(
    paragraph = "Lorem ipsum [...]",
    filename = "./data/RevCon_2015_C1_Austria_05_06.txt",
    stringsAsFactors = FALSE)