r - 一个新列中跨列子集的字数统计

Question

我有以下数据框:

structure(list(g = c("1", "2", "3"), x = c("This is text.", "This is text too.", 
"This is no text"), y = c("What is text?", "Can it eat text?", 
"Maybe I will try.")), class = "data.frame", row.names = c(NA, 
-3L))

我想计算 x 和 y 列中的单词数，并将该值求和以获得一列以及每列使用的单词总数.重要的是我能够对数据进行子集化。结果应该是这样的:

structure(list(g = c("1", "2", "3"), x = c("This is text.", "This is text too.", 
"This is no text"), y = c("What is text?", "Can it eat text?", 
"Maybe I will try."), z = c("6", "8", "8")), class = "data.frame", row.names = c(NA, 
-3L))

我尝试将 str_count("") 与不同的正则表达式结合使用 across 或 apply 但我似乎没有得到解决方案。

我在最初的问题中没有预料到其中包含 NA 单元格的列会出现问题，但我确实预料到了。因此，任何解决方案都需要能够处理 NA 单元格。

Answer 1

此处使用tokenizers 的解决方案:

library(tokenizers)

df <- 
  structure(list(g = c("1", "2", "3"), x = c("This is text.", "This is text too.", 
  "This is no text"), y = c("What is text?", "Can it eat text?", 
  "Maybe I will try.")), class = "data.frame", row.names = c(NA, 
  -3L))

df$z = tokenizers::count_words(df$x) + tokenizers::count_words(df$y)

df
#>   g                 x                 y z
#> 1 1     This is text.     What is text? 6
#> 2 2 This is text too.  Can it eat text? 8
#> 3 3   This is no text Maybe I will try. 8

如果您更喜欢纯 R:

df$z <- rowSums(
  sapply(df[,c("x","y")],function(x)  
    sapply(gregexpr("\\b\\w+\\b", x) , function(x) 
      if(x[[1]] > 0) length(x) else 0)))

请注意，\w+ 匹配所有单词，\b 匹配单词边界，尽管我相信“\w”就足够了