Preg匹配大写和小写用户输入

Question

I'm working on a shopping cart that has coupons and the owner has told me that the customers seem unwilling to use the proper casing for the issued coupons and are annoying the staff with constant complaints that the coupons don't work.

I was initially going to simply strtoupper() the user input, but then this would require that the owner use only uppercase coupon codes and that makes no sense.

I'd like to do a preg_match() on the user input and simply allow it to match if all the characters are correct and ignore case altogether. But alas ... I have NO idea how to work with regex to get what I need.

This what I have now:

strtoupper ($this->request->post['coupon'])

and as I said this works great against an uppercase coupon code from the db but forces the owner to uppercase all their codes.

Any help would be greatly appreciated.

-V

Answer 1

Simply convert both to the same case and compare:

if(strtolower($input) == strtolower($check))

Even better, use strcasecmp() to do a binary safe case-insensitive string comparison:

if (strcasecmp($input, $check) == 0)

Answer 2

It depends on how you check the coupon codes. If you're running a database query, SQL and friends allow you to perform a case-insensitive query. If you're comparing them one-by-one against eg a configuration file, then instead of saying if (code_entered === valid_code) , say if (strtolower(code_entered) === strtolower(valid_code)) . Otherwise, we'll need to know how the actual comparison is happening, as that's the important part.

Answer 3

"this would require that the owner use only uppercase coupon codes and that makes no sense."

From the way you describe your situation, it actually does seem to make sense to store these coupon codes in consistent case (either upper or lower) to match the consistent case (either strtoupper 'd or strtolower 'd) of the customer input.

That said, regexp case-insensitive matching is achieved using the /i modifier.

But strcasecmp() , which has already been suggested, is most likely a better solution.