刪除R中的字符串中最後兩個單詞之間的空白

Question

我試圖刪除包含多個字符串的數據框中最後兩個單詞之間的空白。我曾嘗試使用gsub，但我的嘗試gsub("(\\s){1}$","",df1$V1)似乎相當錯誤！ df1是我的數據集，df2是我之後的結果。

df1 <- data.frame(V1=c("Apple Pear Orange, AAA 111", "Grapes Banana Pear . BBB 222", "Orange Kiwi Melon , CCC 333", "Apple DDD 444", "Kiwi Melon Orange CCC 333", "Apple Pear Orange, AAA 111", "Tomato Cucumber EEE 222", "Seagull Pigeon ZZZ 111"), stringsAsFactors = F) 

df2 <- data.frame(V1=c("Apple Pear Orange, AAA111", "Grapes Banana Pear . BBB222", "Orange Kiwi Melon , CCC333", "Apple DDD444", "Kiwi Melon Orange CCC333", "Apple Pear Orange, AAA111", "Tomato Cucumber EEE222", "Seagull Pigeon ZZZ111"), stringsAsFactors = F) 

Answer 1

甚至這樣的：

gsub("(.*)\\s","\\1",df1$V1) 

Answer 2

您可以使用捕捉組：

sub("(.*)\\s+([^\\s]+)$", "\\1\\2", df1$V1) 
#[1] "Apple Pear Orange, AAA111" "Grapes Banana Pear . BBB222" "Orange Kiwi Melon , CCC333" "Apple DDD444"    
#[5] "Kiwi Melon Orange CCC333" "Apple Pear Orange, AAA111" "Tomato Cucumber EEE222"  "Seagull Pigeon ZZZ111" 

這捕獲作爲第一組中的任何數目的字符，然後1+空格和第二組1+不在位，直到的結束字符串。然後它只提取兩個捕獲組，而沒有間隔。

Answer 3

都會響起Docendo的回答，您可以使用\\w+匹配任何長度的話：

gsub("(\\w+)\\s+(\\w+$)", "\\1\\2" ,df1$V1) 

#[1] "Apple Pear Orange, AAA111" "Grapes Banana Pear . BBB222" "Orange Kiwi Melon , CCC333" 
#[4] "Apple DDD444"    "Kiwi Melon Orange CCC333" "Apple Pear Orange, AAA111" 
#[7] "Tomato Cucumber EEE222"  "Seagull Pigeon ZZZ111" 

然後你可以用同樣的想法與捕獲組。