从文件中自动提取章节（和章节标题）

Question

我需要从 .Rmd 文件中提取所有小节（用于进一步的文本分析）及其标题（例如，来自 tidy-text-mining 本书的 01-tidy-text.Rmd： https://raw.githubusercontent.com/dgrtwo/tidy-text-mining/master/01-tidy-text.Rmd)

据我所知，一个部分从 ## 符号开始，一直运行到下一个 #、## 符号或文件末尾。

整个文本已被提取（使用 dt <- readtext("01-tidy-text.Rmd"); strEntireText <-dt[1,1]）并且位于变量 strEntireText.

我想为此使用 stringr。或 stringi，大致如下：

 strAllSections <- str_extract(strEntireText , pattern="...")
 strAllSectionsTitles <- str_extract(strEntireText , pattern="...")

请提出您的解决方案。谢谢

本练习的最后 objective 是能够从 .Rmd 文件自动创建 data.frame，其中每一行对应于每一节（和子节），列包含：节标题、部分标签、部分文本本身，以及一些其他 section-specific 细节，稍后将提取这些细节。

Answer 1

这是一个使用 tidyverse 方法的示例。这不一定适用于您拥有的任何文件——如果您正在使用降价，您可能应该尝试找到合适的降价解析库，正如 Spacedman 在他的评论中提到的那样。

library(tidyverse)

## A df where each line is a row in the rmd file.
raw <- data_frame(
  text = read_lines("https://raw.githubusercontent.com/dgrtwo/tidy-text-mining/master/01-tidy-text.Rmd")
)

## We don't want to mark R comments as sections.
detect_codeblocks <- function(text) {
  blocks <- text %>%
    str_detect("```") %>%
    cumsum()

  blocks %% 2 != 0
}

## Here is an example of how you can extract information, such
## headers, using regex patterns.
df <-
  raw %>%
  mutate(
    code_block = detect_codeblocks(text),
    section = text %>%
      str_match("^# .*") %>%
      str_remove("^#+ +"),
    section = ifelse(code_block, NA, section),
    subsection = text %>%
      str_match("^## .*") %>%
      str_remove("^#+ +"),
    subsection = ifelse(code_block, NA, subsection),
    ) %>%
  fill(section, subsection)

## If you wish to glue the text together within sections/subsections,
## then just group by them and flatten the text.
df %>%
  group_by(section, subsection) %>%
  slice(-1) %>%                           # remove the header
  summarize(
    text = text %>%
      str_flatten(" ") %>%
      str_trim()
  ) %>%
  ungroup()

#> # A tibble: 7 x 3
#>   section                          subsection  text                       
#>   <chr>                            <chr>       <chr>                      
#> 1 The tidy text format {#tidytext} Contrastin… "As we stated above, we de…
#> 2 The tidy text format {#tidytext} Summary     In this chapter, we explor…
#> 3 The tidy text format {#tidytext} The `unnes… "Emily Dickinson wrote som…
#> 4 The tidy text format {#tidytext} The gutenb… "Now that we've used the j…
#> 5 The tidy text format {#tidytext} Tidying th… "Let's use the text of Jan…
#> 6 The tidy text format {#tidytext} Word frequ… "A common task in text min…
#> 7 The tidy text format {#tidytext} <NA>        "```{r echo = FALSE} libra…

从文件中自动提取章节（和章节标题）

Automatically extracting Sections (and section Titles) from a file

r

stringr

stringi

tidytext

read-text