R中的字符串模式操作

Question

我試圖從R中的一堆文本中找到主持人和訪客姓名。

示范文本 -

dat = data.frame(Series = c('England in Australia ODI Match',
'Prudential Trophy (Australia in England)',
'Pakistan in New Zealand ODI Match',
'Prudential Trophy (New Zealand in England)',
'Prudential Trophy (West Indies in England)',
'Australia in New Zealand ODI Series',
'Texaco Trophy (Australia in England)'))

我想要創建兩個新列。所需的輸出如下所示 -

Visitor     Host
England     Australia
Australia   England
Pakistan    New Zealand
New Zealand England
West Indies England
Australia   New Zealand

我正在嘗試以下功能，但它不完整。

dat$Host = sub(" in.*", "", dat$Series)

Answer 1

這是你想要的東西：

re = regexpr("((New |West )?\\w+) in ((New |West )?\\w+)", dat$Series)
rm = regmatches(dat$Series, re)
d = do.call(rbind,strsplit(rm, " in "))
colnames(d) = c("Visitor","Host")

輸出：

     Visitor       Host         
[1,] "England"     "Australia"  
[2,] "Australia"   "England"    
[3,] "Pakistan"    "New Zealand"
[4,] "New Zealand" "England"    
[5,] "West Indies" "England"    
[6,] "Australia"   "New Zealand"
[7,] "Australia"   "England"