r将列拆分为多个列

Question

我试图根据分界模式将数据帧中的一列字符串拆分为多个列，即一列字符串＆＃34; b＆＃34;和＆＃34; c d＆＃34;应分成两列，一列用＆＃34; a＆＃34; ＆＃34; c＆＃34;和另一个＆＃34; b＆＃34;和＆＃34; d＆＃34;。在我的例子中，分隔模式是任何不包含a-zA-Z0-9@.

的字符序列

根据建议here我尝试使用stringr。但是，似乎str_split对空格的数量很敏感？

> xxx<-str_split_fixed(c("a b", "c  d")," ",3)
> xxx
      [,1] [,2] [,3]
 [1,] "a"  "b"  ""  
 [2,] "c"  ""   "d" 

> xxx<-str_split_fixed(c("a b", "c  d"),"[:space:] ",3)
> xxx
      [,1] [,2] [,3]
 [1,] ""   "b"  ""  
 [2,] ""   " d" ""  

> xxx<-str_split_fixed(c("a b", "c  d"),"' '+",3)
> xxx
      [,1]   [,2] [,3]
 [1,] "a b"  ""   ""  
 [2,] "c  d" ""   ""