使用正则表达式检查字符串是否包含单个反斜杠 [英] Check if string contains single backslashes with regex

问题描述

我已经尝试解决这个问题很长时间了，但我就是做不到.

I have tried to fix this for a long time, and i just can't do it.

它可以是任何字符串，但这是一个例子:

It could be any string, but this is an example:

"\This string \contains some\ backslashes\"

我需要制作一个正则表达式，我可以用它来检查字符串是否包含单个反斜杠.

I need to make a regex that i can use to check that the string contains single backslashes.

然后我需要将给定的字符串转换为(我可以进行转换):

I then need to convert the given string into (i can do the conversion):

"\\This string \\contains some\\ backslashes\\"

然后使用正则表达式检查字符串是否不再包含单个反斜杠.

And then use regex to check that the string no long contains single backslashes.

顺便说一句，我不必为此使用正则表达式，我只需要能够以某种方式检查字符串.

Btw i dont have to use regex for this, i just need to be able to check the strings somehow.

推荐答案

您似乎只想检查字符串是否部分匹配正则表达式模式，即，它是否包含前面或后面没有反斜杠的文字反斜杠.

It seems you just want to check if a string matches a regex pattern partially, namely, if it contains a literal backslash not preceded nor followed with a backslash.

使用

(?<!\\)\\(?!\\)

查看正则表达式演示.

Scala 代码示例:

Sample Scala code:

val s = """"\This string\\ \contains some\ backslashes\""""
val rx = """(?<!\\)\\(?!\\)""".r.unanchored
val ismatch = s match {
  case rx(_*) => true
  case _ => false
}
println(ismatch)

查看 Scala 在线演示.

注意:

• """(?<!\\)\\(?!\\)""".r.unchored - 这一行声明了一个正则表达式对象并使模式非锚定，所以match 块
不再需要完整的字符串匹配
• 在match中，我们使用case rx(_*)，因为在模式本身内部没有定义捕获组
• 该模式表示:匹配前面没有反斜杠 ((?<!\\)) 并且后面没有跟的反斜杠 (\\)反斜杠 ((?!\\)).

• """(?<!\\)\\(?!\\)""".r.unanchored - this line declares a regex object and makes the pattern unanchored, so that no full string match is no longer required by the match block
• Inside match, we use case rx(_*) as there is no capturing group defined inside the pattern itself
• The pattern means: match a backslash (\\) that is not preceded with a backslash ((?<!\\)) and is not followed with a backslash ((?!\\)).

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