这很可能是一个愚蠢的问题，但是我已经在Google和Google上搜索了，找不到解决方案。我认为这是因为我不知道用正确的方式来表达我的问题以进行搜索。
我有一个数据框，已将其转换为R中的整洁文本格式，以消除停用词。我现在想“整理”该数据框回到其原始格式。
什么是unnest_tokens的相反/反向命令？
编辑：这是我正在使用的数据的样子。我正在尝试复制Silge和Robinson的Tidy Text书中的分析，但使用的是意大利歌剧librettos。
character = c("FIGARO", "SUSANNA", "CONTE", "CHERUBINO")
line = c("Cinque... dieci.... venti... trenta... trentasei...quarantatre", "Ora sì ch'io son contenta; sembra fatto inver per me. Guarda un po', mio caro Figaro, guarda adesso il mio cappello.", "Susanna, mi sembri agitata e confusa.", "Il Conte ieri perché trovommi sol con Barbarina, il congedo mi diede; e se la Contessina, la mia bella comare, grazia non m'intercede, io vado via, io non ti vedo più, Susanna mia!")
sample_df = data.frame(character, line)
sample_df
character line
FIGARO Cinque... dieci.... venti... trenta... trentasei...quarantatre
SUSANNA Ora sì ch'io son contenta; sembra fatto inver per me. Guarda un po', mio caro Figaro, guarda adesso il mio cappello.
CONTE Susanna, mi sembri agitata e confusa.
CHERUBINO Il Conte ieri perché trovommi sol con Barbarina, il congedo mi diede; e se la Contessina, la mia bella comare, grazia non m'intercede, io vado via, io non ti vedo più, Susanna mia!
我将其转换为整洁的文字，因此可以摆脱停用词：
tribble <- sample_df %>%
unnest_tokens(word, line)
# Get rid of stop words
# I had to make my own list of stop words for 18th century Italian opera
itstopwords <- data_frame(text=mystopwords)
names(itstopwords)[names(itstopwords)=="text"] <- "word"
tribble2 <- tribble %>%
anti_join(itstopwords)
现在我有这样的事情：
text word
FIGARO cinque
FIGARO dieci
FIGARO venti
FIGARO trenta
...
我想将其恢复为字符名称和相关行的格式，以查看其他内容。基本上，我希望文本使用以前的格式，但是删除了停用词。
最佳答案
这不是一个愚蠢的问题！答案在某种程度上取决于您要尝试执行的操作，但是如果我想使用dplyr的group_by()函数以整理后的格式将文本恢复为原始格式，这将是我的典型方法。
首先，让我们从原始文本转换为整齐的格式。
library(tidyverse)
library(tidytext)
tidy_austen <- janeaustenr::austen_books() %>%
group_by(book) %>%
mutate(linenumber = row_number()) %>%
ungroup() %>%
unnest_tokens(word, text)
tidy_austen
#> # A tibble: 725,055 x 3
#> book linenumber word
#> <fct> <int> <chr>
#> 1 Sense & Sensibility 1 sense
#> 2 Sense & Sensibility 1 and
#> 3 Sense & Sensibility 1 sensibility
#> 4 Sense & Sensibility 3 by
#> 5 Sense & Sensibility 3 jane
#> 6 Sense & Sensibility 3 austen
#> 7 Sense & Sensibility 5 1811
#> 8 Sense & Sensibility 10 chapter
#> 9 Sense & Sensibility 10 1
#> 10 Sense & Sensibility 13 the
#> # … with 725,045 more rows
文字整齐了！但是我们可以将其整理回原来的形式。我通常使用dplyr中的
group_by()和summarize()以及stringr中的str_c()来解决这个问题。在这种情况下，最后的文本是什么样的？tidy_austen %>%
group_by(book, linenumber) %>%
summarize(text = str_c(word, collapse = " ")) %>%
ungroup()
#> # A tibble: 62,272 x 3
#> book linenumber text
#> <fct> <int> <chr>
#> 1 Sense & Sensib… 1 sense and sensibility
#> 2 Sense & Sensib… 3 by jane austen
#> 3 Sense & Sensib… 5 1811
#> 4 Sense & Sensib… 10 chapter 1
#> 5 Sense & Sensib… 13 the family of dashwood had long been settled…
#> 6 Sense & Sensib… 14 was large and their residence was at norland…
#> 7 Sense & Sensib… 15 their property where for many generations th…
#> 8 Sense & Sensib… 16 respectable a manner as to engage the genera…
#> 9 Sense & Sensib… 17 surrounding acquaintance the late owner of t…
#> 10 Sense & Sensib… 18 man who lived to a very advanced age and who…
#> # … with 62,262 more rows
由reprex package（v0.3.0）创建于2019-07-11