在R中，当字符串长度可变时，如何分隔字符串的开始、中间和结尾？

Question

例如我有这个，

Full Name
1 Fred Peters 
2 Fred Lukas Peters
3 Fred Lukas James Peters
4 Fred Lukas of James Peters

但想拥有，

First     Middle          Last
1 Fred                      Peters
2 Fred      Lukas           Peters
3 Fred      Lukas James     Peters
4 Fred      Lukas of James  Peters
5 Michael                   Smith

我知道如何使用 separate(Full Name, c("First","Middle","Last"), " ")

但是我很困惑如何告诉 R 字符串的最后一个单词应该始终在最后一列中，并且 First 和 Last 之间的所有内容都应该介于两者之间。

Answer 1

我们可以使用extract

library(dplyr)
library(stringr)
library(tidyr)
df1 %>%
    mutate(`Full Name` = str_replace(`Full Name`, 
     '^(\\w+)\\s+(\\w+)$', "\\1 NA \\2")) %>%
     extract(`Full Name`, into = c("First","Middle","Last"), 
          "^(\\S+)\\s+(.*)?\\s+(\\S+)$", convert = TRUE)

-输出

   First         Middle   Last
1  Fred             NA Peters
2  Fred          Lukas Peters
3  Fred    Lukas James Peters
4  Fred Lukas of James Peters

数据

df1 <- structure(list(`Full Name` = c("Fred Peters", "Fred Lukas Peters", 
"Fred Lukas James Peters", "Fred Lukas of James Peters")), 
class = "data.frame", row.names = c("1", 
"2", "3", "4"))