我需要删除所有内容。 与模式不符

Question

I need to remove all dots from text unless they match a pattern [0-9]+.[0-9]+ for example if the following text is my input:

abc. def. 123.45 ... 12. 

the output should look like this:

abc def 123.45 12

Thanks

Answer 1

If the language you are using supports lookarounds you can use this regular expression:

(?<![0-9])\.|\.(?![0-9])

This matches dots that either aren't preceded by a digit, or aren't followed by a digit.

Example for C#:

string result = Regex.Replace(input, @"(?<![0-9])\.|\.(?![0-9])", "");

See it working online: ideone

Answer 2

If your regex flavor supports negative lookarounds (which .NET does fabulously) you can use this:

(?<!\d)\.|\.(?!\d)

This will only match dots that have either a non-digit character before or after them. Simply replace the result with an empty string.

If not, then you can do this:

(?|(^|\D)\.|\.($|\D))

And replace with $1 . This does the same, but includes that additional character in the match. The replacement puts that matched character back in place.