preg_match_all with space and comma delimiters

Question

I've managed to get part of the preg_match returning the values I need, but am unable to get the correct syntax to return what follows that string after a comma. Any assistance is appreciated - thanks

$regex = '{loadsegment+(.*?)}';
$input = '{loadsegment 123,789}';
preg_match_all($regex, $input, $matches, PREG_SET_ORDER);

Current result :

$matches [0] [0] {loadsegment 123}
             [1] 123,789

Desired result :

$matches [0] [0] {loadsegment 123,789}
             [1] 123
             [2] 789

Stereotypy

Answer 1

You need two capturing groups before and after a comma (and delimiters):

$regex = "/{loadsegment (\d+),(\d+)}/";

Also, I'm using \d which is shorthand for a digit, instead of .*?, which is anything.

I also removed t+ for t, since t+ will match t one or more times, which doesn't seem like what you want to do.

To make the second group optional, you'd use the ? modifier:

/{loadsegment (\d+),(\d+)?}/

But this still requires the comma. You can make it optional as well...

/{loadsegment (\d+),?(\d+)?}/

... but now your regex will match:

{loadsegment 123,}

which we probably dont want. So, we include the comma in the optional second group, like this:

/{loadsegment (\d+)(?:,(\d+))?}/

Explanation (minus the delimiters):

{loadsegment   - Match "{loadsegment "
(\d+)          - Match one or more digits, store in capturing group 1
(?:            - Non-capturing group (so this won't be assigned a capturing group number
    ,          - Match a comma
    (\d+)      - Match one or more digits, store in capturing group 2
)
?              - Make the entire non-capturing group optional

Demo at RegExr

Halophyte

@Stereotypy - You were pretty close! The more you use it, the more familiar you will become with it. – Halophyte

Unfortunately, every time I use it, it's a completely different scenario than last time, and lose what I've already managed to figure out, lol....having "Regex Power" would beat any Super Hero power in my book! – Stereotypy

is there syntax to make the 2nd group optional, or better yet a default if it's not there? – Stereotypy

Sure, just put a question mark after it. But, if you want it to be optional, you probably also want to omit the comma. So, I can edit my answer with a better regex to do that. – Halophyte

I always want to send money when someone goes the extra mile like you are - yes, the 2nd group is optional, and would not have a comma if it were excluded. – Stereotypy

Well, I'll nominate you for the Regex Emmy awards when it's time - thanks so very much, and most especially for the added explanation of how it comes together. – Stereotypy

@Stereotypy - Hah! Sounds good to me. Not a problem, glad I could help! – Halophyte