我试图弄清楚为什么我的一个regex命令有效，而另一个则无效。这是从中提取两个字符串的示例。由于刮擦而产生的新行垃圾具有一致性，因此我尽最大可能利用了这一点：
"\n\tMenghe a'Nyam\n\t\n\n \n\n \n\n \n\n \n Position:\n \n Forward\n\n\n\n 6-5, 215lb (196cm,
97kg) \n \n\n \n\n \n \n \n\n School: Canisius\n\n\n\n\n\n More player info\n\n\n\n\n\n"
"\n\tJordan Aaberg\n\t\n\n \n\n \n\n \n\n \n Position:\n \n Guard\n\n\n\n 6-9, 225lb (206cm,
102kg) \n \n\n Hometown: Rothsay, MN\n\n\n\n \n\n High School: Rothsay\n\n\n\n \n \n \n\n
School: North Dakota State\n\n\n\n\n\n More player info\n\n\n\n\n\n"
我的目标是从中获取所需数据，例如位置（分别为前锋，后卫），最重要的是，身高（分别为6-5、6-9）。我成功完成了以下工作：
test <- df %>%
mutate(position = str_extract(player, "(?<=Position:\n \n ).*?(?=\n\n\n\n \\d-\\d)"))
但是，当我按照类似的方法为高度添加另一个col时，它返回NA：
test <- df %>%
mutate(position = str_extract(player, "(?<=Position:\n \n ).*?(?=\n\n\n\n \\d-\\d)")) %>%
mutate(height = str_extract(player, "(?<=\\w+\n\n\n\n ).*?(?=, \\d{3}lb)"))
如果有帮助，以下是上述df前3行调用的结果示例：
structure(list(player = c("\n\tMenghe a'Nyam\n\t\n\n \n\n \n\n \n\n \n Position:\n \n Forward\n\n\n\n 6-5, 215lb (196cm, 97kg) \n \n\n \n\n \n \n \n\n School: Canisius\n\n\n\n\n\n More player info\n\n\n\n\n\n" ,
"\n\tJordan Aaberg\n\t\n\n \n\n \n\n \n\n \n Position:\n \n Forward\n\n\n\n 6-9, 225lb (206cm, 102kg) \n \n\n Hometown: Rothsay, MN\n\n\n\n \n\n High School: Rothsay\n\n\n\n \n \n \n\n School: North Dakota State\n\n\n\n\n\n More player info\n\n\n\n\n\n" ,
"\n\tKarl Aaker\n\t\n\n \n\n \n\n \n\n \n Position:\n \n Forward\n\n\n\n 6-5, 210lb (196cm, 95kg) \n \n\n Hometown: Reno, NV\n\n\n\n \n\n \n \n \n\n School: Portland\n\n\n\n\n\n More player info\n\n\n\n\n\n"
), position = c("Forward", "Forward", "Forward"), height = c(NA_character_,
NA_character_, NA_character_)), row.names = c(NA, 3L), class = "data.frame")
您可以+在之后删除，\w因为ICU正则表达式引擎不支持lookbehinds内部的无限长度的字符串匹配模式，并用于\s匹配任何空格：
test <- df %>%
mutate(position = str_extract(player, "(?<=Position:\n \n ).*?(?=\n\n\n\n \\d-\\d)")) %>%
mutate(height = str_extract(player, "(?<=\\w\n{4}\\s{2}).*?(?=,\\s+\\d{3}lb)"))
参见正则表达式演示
细节
(?<=\w\n{4}\s{2}) -在比赛之前，应该有一个单词char，然后是4个换行符，然后是任意2个空白字符.*? -除换行符以外的任何0个或更多字符，应尽可能少(?=,\s+\d{3}lb)-比赛结束后，应立即包含一个逗号，一个或多个空格字符，3位数字和lb子字符串。本文收集自互联网，转载请注明来源。
如有侵权，请联系 [email protected] 删除。
我来说两句