所以你真正想做的是删除一个前面有字母数字字符的点，然后是一个或两个破折号nderscores？然后你可以使用积极的先行断言来做到这一点：

搜索 \\\\。（？= __ | - ）并替换为空字符串。

如果您还想确保在下划线/破折号后跟随另一个字母数字字母，您可以：

搜索 \ b \。（？= __（？= [A-Za-z0-9]）| -\b）并替换为空字符串。

I'm trying to replace all occurences of .__ with __ and .- with - so the following:

article.__authors.__item ...would become... article__authors__item

...and...

bucket.__water.-half ...would become... bucket__water-half

I started with the .__ part and came up with \b\.__\b as my regex but http://gskinner.com/RegExr/ doesn't seem to like it...

This works for the 2nd match though \b\.-\b

Is there a better way?

Cheers, Nick

So what you actually want to do is to remove a dot that is preceded by an alphanumeric character and followed by either a dash or two underscores? Then you can do this using positive lookahead assertions:

Search for \b\.(?=__|-) and replace with the empty string.

If you also want to make sure that another alphanumeric letter follows after the underscores/dash, you can:

Search for \b\.(?=__(?=[A-Za-z0-9])|-\b) and replace with the empty string.