R语言DataFrame文本列按停用词列表替换指定词汇且保留词序的实现问题

你的代码出错的核心原因是str_replace的第一个输入参数被你写成了逻辑判断表达式，返回的是布尔值而非待处理的单词文本，所以最终得到的是逻辑向量而非替换后的单词列表，同时冗余的循环和多层lapply也增加了逻辑混乱。
以下是满足需求的完整实现： #

1. 基础数据定义 #

# 示例数据集
df <- structure(list(ID = 1:3, Text = c("there was not clostridium", "clostridium difficile positive", "test was OK but there was clostridium")), class = "data.frame", row.names = c(NA, -3L)) 
# 停用词正则模式（避免和基础函数stop重名，改名stop_pattern）
stop_pattern <- paste0(c("was", "but", "there"), collapse = "|")

2. 处理代码 #

无需循环、无需merge类函数，单层遍历即可实现，自动保留原有词序：

library(tokenizers)
library(stringr)

# 生成分词列表
df$Words <- tokenize_words(df$Text, lowercase = TRUE)

# 批量替换停用词
df$clean <- lapply(df$Words, function(word_vec) {
  str_replace(word_vec, pattern = stop_pattern, replacement = "REPLACED")
})

# 可选：将列表列转为逗号分隔的字符串，方便打印查看
df$Words <- sapply(df$Words, paste, collapse = ", ")
df$clean <- sapply(df$clean, paste, collapse = ", ")

3. 输出结果 #

打印df即可得到你预期的效果：

ID                                  Text                                       Words                                                           clean
1  1             there was not clostridium                there, was, not, clostridium                      REPLACED, REPLACED, not, clostridium
2  2        clostridium difficile positive            clostridium, difficile, positive                             clostridium, difficile, positive
3  3 test was OK but there was clostridium test, was, ok, but, there, was, clostridium test, REPLACED, ok, REPLACED, REPLACED, REPLACED, clostridium

内容的提问来源于stack exchange，提问作者onhalu