r - 将前后单词连接到与 R 中的条件匹配的单词

Question

我需要连接满足条件的词的前一个词和后一个词。具体来说，那些符合逗号条件的人。

vector <- c("Paulsen", "Kehr,", "Diego",    "Schalper", "Sepúlveda,", "Diego")

#I know how to get which elements meet my condition:

grepl(",", vector)
#[1] FALSE  TRUE FALSE FALSE  TRUE FALSE 

期望的输出:

print(vector_ok)
#[1] "Paulsen Kehr, Diego", "Schalper Sepúlveda, Diego"

提前致谢!

Answer 1

您可以使用 grep() 获取带逗号的字符串的位置，将这些扩展为序列 +/- 1，并使用它来索引然后折叠原始向量。

idx <- grep(",", vector)
seqs <- Map(`:`, idx-1, idx+1)
sapply(seqs, function(x) paste(vector[x], collapse = " "))

[1] "Paulsen Kehr, Diego"       "Schalper Sepúlveda, Diego"