移除两个字符串之间的字符串

Question

假设我有以下向量：

df<- c("@Accessoires A-B [COLL]", "@Accessoires C-D [COLL]",
        "@Components A-D [COLL]","@Components [COLL]", 
        "@Accessoires [COLL]", "@Components H-Z [COLL]")

我想移除A-B或C等字串的中间部分。这是一个例子，在我的数据，有许多可能性的字母组合。

因此，所需的输出将是：

"@Accessoires [COLL]" 
"@Accessoires [COLL]" 
"@Components [COLL]"  
"@Components [COLL]"  
"@Accessoires [COLL]" 
"@Components [COLL]" 

我的问题是，如何在R中实现这一点，而不必定义所有字母组合？

Answer 1

您可以使用sub()和一些正则表达式：

sub("\\s[A-Z]-[A-Z]\\s", " ", df)
[1] "@Accessoires [COLL]" "@Accessoires [COLL]" "@Components [COLL]"  "@Components [COLL]" 
[5] "@Accessoires [COLL]" "@Components [COLL]" 

正则表达式归结为：

• \\s：一个空间
• [A-Z]：任何(英文)大写字母。

顺便说一句，您的df是向量，但不是data.frame。

df <- c(
  "@Accessoires A-B [COLL]", "@Accessoires C-D [COLL]","@Components A-D [COLL]",
  "@Components [COLL]", "@Accessoires [COLL]","@Components H-Z [COLL]"
)
is.data.frame(df)
[1] FALSE

Answer 2

在空间上拆分，得到第一个也是最后一个元素：

sapply(strsplit(df, " "), function(i) paste(head(i, 1), tail(i, 1)))

# [1] "@Accessoires [COLL]" "@Accessoires [COLL]" "@Components [COLL]" 
# [4] "@Components [COLL]"  "@Accessoires [COLL]" "@Components [COLL]" 

Answer 3

df不是data.frame，而是字符向量。您可以使用gsub删除空格之间的任何内容。

gsub(" .* ", " ", df)
[1] "@Accessoires [COLL]" "@Accessoires [COLL]" "@Components [COLL]"  "@Components [COLL]"  "@Accessoires [COLL]" "@Components [COLL]" 

这就是你要找的吗？