正则表达式用两个以上连续字符替换单词 [英] regex to replace words with more than two consecutive characters

问题描述

如何检测一个单词中存在两个以上连续字符并删除该单词？

How can I detect the presence of more than two consecutive characters in a word and remove that word?

我似乎能够做到这一点：

I seem to be able to do it like this:

# example data
mystring <- c(1, 2, 3, "toot", "tooooot")
# clunky regex
gsub("^[[:alpha:]]$", "", gsub(".*(.)\\1+\\1", "", mystring)) 
[1] "1"    "2"    "3"    "toot" "" 

但是我敢肯定有一种更有效的方法。我怎么只用一个 gsub 就能做到？

But I'm sure there is a more efficient way. How can I do it with just one gsub?

推荐答案

使用 grepl 代替。

mystring <- c(1, 2, 3, "toot", "tooooot", "good", "apple", "banana")
mystring[!grepl("(.)\\1{2,}", mystring)]
## [1] "1"      "2"      "3"      "toot"   "good"   "apple"  "banana"

**说明**

\\1 匹配第一组（在这种情况下（。））。 {2，} 指定前一个字符至少应匹配2次或更多次。由于我们要匹配重复3次或更多次的任何字符-首次出现（。），因此 \\1 需要匹配2倍以上的矿石。

** Explanation**
\\1 matches first group (in this case (.) ). {2,} specifies that preceding character should be matched atleast 2 times or more. Since we want to match any character repeated 3 times or more - (.) is first occurrence, \\1 needs to be matched 2 times ore more.

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