与unnest_tokens相反 [英] Opposite of unnest_tokens

问题描述

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，找不到解决方法.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.

This is most likely a stupid question, but I've googled and googled and can't find a solution. I think it's because I don't know the right way to word my question to search.

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.

I have a data frame that I have converted to tidy text format in R to get rid of stop words. I would now like to 'untidy' that data frame back to its original format.

unnest_tokens的反/反命令是什么?

What's the opposite / inverse command of unnest_tokens?

这是我正在使用的数据的样子.我试图从Silge和Robinson的整洁的文字书中复制分析，但使用的是意大利歌剧librettos.

here is what the data I'm working with look like. I'm trying to replicate analyses from Silge and Robinson's Tidy Text book but using Italian opera 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:

I turn it into tidy text so I can get rid of stop words:

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)

现在我有这样的东西:

text    word
FIGARO  cinque
FIGARO  dieci
FIGARO  venti
FIGARO  trenta
...

我想重新将其转换为字符名称和相关行的格式，以查看其他内容.基本上，我希望文本使用与以前相同的格式，但是要删除停用词.

I would like to get it back into the format of character name and the associated line to look at other things. Basically I would like the text in the same format it was before, but with stop words removed.

推荐答案

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()函数以整齐的形式对文本进行处理后，将文本恢复为原始格式，这将是我的典型方法.

Not a stupid question! The answer depends a bit on exactly what you are trying to do, but here would be my typical approach if I wanted to get my text back to its original form after some processing in its tidied form, using the group_by() function from dplyr.

首先，让我们从原始文本转换为整齐的格式.

First, let's go from raw text to a tidied format.

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

文本现在很整洁！但是我们可以将其弄乱，回到原来的形式.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.在这种特殊情况下，最后的文本是什么样的?

The text is tidy now! But we can untidy it, back to something sort of like its original form. I typically approach this using group_by() and summarize() from dplyr, and str_c() from stringr. What does the text look like at the end, in this particular case?

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软件包(v0.3.0)于2019-07-11创建 sup>}

^{Created on 2019-07-11 by the reprex package (v0.3.0)}

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