查找每个逗号后的第二个空格

_{This is a follow up to this question: Concatenate previous and latter words to a word that match a condition in R https://stackoverflow.com/questions/58551389/concatenate-previous-and-latter-words-to-a-word-that-match-a-condition-in-r}

我正在寻找一个正则表达式，它可以在逗号之后的第二个空格处分割字符串。看下面的例子：

vector <- c("Paulsen", "Kehr,", "Diego", 
            "Schalper", "Sepúlveda,", "Alejandro",
             "Von Housen", "Kush,", "Terry")

X <- paste(vector, collapse = " ")
X

## this is the string I am looking to split:
"Paulsen Kehr, Diego Schalper Sepúlveda, Diego Von Housen Kush, Terry"

每个逗号后的第二个空格是我的标准regex /questions/tagged/regex。所以，我的输出将是：

"Paulsen Kehr, Diego"
"Schalper Sepúlveda, Alejandro"
"Von Housen Kush, Terry"

我想出了一个模式，但不太有效。

[^ ]+ [^ ]+, [^ ]+( )

与它一起使用strsplit删除所有单词而不是在 group-1 处拆分（即[^ ]+ [^ ]+, [^ ]+(group-1)） 仅有的。我想我只需要排除完整的匹配项并仅与后面的空格匹配。 --正则表达式演示 https://regex101.com/r/z383ig/17

strsplit(X, "[^ ]+ [^ ]+, [^ ]+( )")

# [1] "" [2] "" [3] "Von Housen Kush, Terry"

谁能想到一个regex /questions/tagged/regex为了找到每个逗号后的第二个空格?

您可以使用

> strsplit(X, ",\\s+\\S+\\K\\s+", perl=TRUE)
[[1]]
[1] "Paulsen Kehr, Diego"           "Schalper Sepúlveda, Alejandro" "Von Housen Kush, Terry"

See the 正则表达式演示 https://regex101.com/r/1BRzKj/1

Details

• ,- 一个逗号
• \s+- 1+ 空格
• \S+- 1+ 个非空格
• \K- 匹配重置运算符丢弃迄今为止匹配的所有文本
• \s+- 1+ 空格