Question

我在从单词列表中提取第一个单词时遇到麻烦。我试过子字符串，gsub和str_extract，但仍然没有弄清楚。请指教。谢谢。这是我想要做的：

Word
"c("print", "printing", "prints")"
"c("take", "takes", "taking")"
"c("score", "scoring", "scored")"

我正在尝试从列表中提取第一个单词，如下所示：

Extracted
print
take
score

Answer 1

您可以仅将purrr::map与索引参数一起使用，如下所示：

如果您希望将输出作为列表返回：

  > purrr::map(Word, 1)
  # [[1]]
  # [1] "print"
  #
  # [[2]]
  # [1] "take"
  #
  # [[3]]
  # [1] "score"

如果您希望它作为向量返回：

  > purrr::map_chr(Word, 1)
  # [1] "print" "take"  "score"

Answer 2

仅使用基数R

##Just to recreate the data
df <- tibble(
  Word= list(c("print", "printing", "prints"),c("take", "takes", "taking"),c("score", "scoring", "scored")))

###
df$Extracted <- sapply(1:length(df$Word), function(i)df$Word[[i]][1])

如何从单词列表中提取第一个单词？

2 个答案: