Question

for a factoring program I’m making I’m wondering if anyone can help me out.

Say I have an equation like

5x^2 + 3x + 7

I need to isolate 5, 3 and 7

although it could come up with negative signs are oppose to positive signs aswell.

Is there any efficient regex that would do it? as the way I’m doing it right now is fairly long and not very efficient.

Answer 1

Try with following regex:

(?:^|[^\^])((?:\- *)?\d+)

Combine it with preg_match_all function.

Explanation:

It matches all digits

(\d+)

with optional negative sign (whitespacesbetween allowed)

(?:\- *)?

that are not followed with ^ sign

[^\^]

or are on the beggining of the string

^

(so there is ^|[^\^]) matched in non-captured group

(?:^|[^\^])