vbs regex: match the text between ONLY the FIRST 2 underscores

I'm doing some filename scraping with VBS, if the file name was called

hello_world_2012_is_not the end of the world.pdf

then the regex should match the word "world" and nothing else.

I tried this:

[_][^_]+(?开发者_运维知识库=_)

but it gets everything that is between two underscores. How do I only select the first occurrence?

I suggest the following regex:

/^[^_]*_([^_]*)_/

Explanation:

^        # Anchor the search to the start of the string
[^_]*    # Match any number of non-underscores, don't capture them
_        # Match the first underscore
([^_]*)  # Match any number of non-underscores, do capture them
_        # Match the second underscore.

Then the first capturing group ($1) will contain world, and the regex won't match anywhere else in the string.

The regex itself should look something like this:

_([^_]*)_

The string is captured into group 1.

Alternatively, use string functions to locate the first 2 underscores and then extract what's between them.