Question

I’m trying to find a regex that will match a specific expression in the following format:

name = value

However, I need it to not match:

name.extra = value

I have the following regex:

([\w\@\-]+) *(\=|\>|\>\=|\<|\<\=) *([^\s\']+)

which matches the first expression, but also matches the second expression (extra = value).

I need a regex that will match only the first expression and not the second (i.e. with a dot).

Answer 1

Negative lookbehind assertion (?<!) might be what you are looking for.

For a simple assignment: (?<!\.)\b(\w+)\s*=\s*(\w+)

summary:

• (?<!\.) = prevent the character . at that location
• \b = beginning of a word

The captured words are:

• \1 = destination name
• \2 = source name

and using the regex you specified, this should give something near this:

(?<!\.)\b([\w\@\-]+) *(\=|\>|\>\=|\<|\<\=) *([^\s\']+)