Question

If I have a formula similar to this: a + b – c * (exp(a*b) ) / 3

I want to match only variables(a, b, c). For me, [a-zA-Z]+ does the job. However I do not want to match exp function. How can I achieve this with regular expressions? I use javascript.

Answer 1

([a-zA-Z]+)\b(?!\s*\()

more common notion of acceptable variable names would be

\b([a-zA-Z_]\w*)\b(?!\s*\()

with dots in function names it becomes

(?:[^.]|^)\b([a-zA-Z]+)\b(?!(\.|\s*\())

(the variable will be in the first capturing match)