How do you match a string that precedes and/or succeeds a string or character that matches a given pattern?

I couldn't find a general question on the Internet, so I figured I'd ask it here. What syntax would I use to match a string that precedes another string or character that matches a given pattern.

Example Suppose I have a string like this:

Lorem ipsum: dolor sit amet; consectator:

What regex would return "Lorem ipsum" and "Lorem ipsum: dolor sit amet; consectator" because they precede a :?

What regex would return "dolor sit amet; consectator:" because they succeed a :? Etc.

Solution 1:

• ^.+?(?=:) matches Lorem ipsum
• ^.+(?=:) matches Lorem ipsum: dolor sit amet; consectator
• (?<=:).+ matches dolor sit amet; consectator:

Have a play with explanation here