Having fun with regular expressions but want a more dynamic

[j.smith1981]

Hi there,

 

I was wondering if I could pick someones brains please?

 

I am doing some work in regular expressions again, I thought why not have some fun with it, well I have setup this literal example but a bit baffled with what I am trying to do.

 

Here's my logic:

<?php
preg_match('/index.php\?cat=\d\d&post=\d\d/', 'index.php?cat=25&post=65', $matches);

 

What I would like to do is allow the \d\d (2 digits) to be anything like say i don't know 1 10 even 100000 you see?

 

Is this possible if so how? I am trying to think about this critically but failing to do so to add to this, just though it would be fun any helps much appreciated,

 

Jeremy.

[Adam]

If you have two digits directly next to each other, you just need to use one \d because it will match both at once.

[j.smith1981]

Tried this:

 

<?php
preg_match('/index.php\?cat=\d&post=\d\d/', 'index.php?cat=25&post=65', $matches);

 

Does not now come up with any results, there must be a method for saying up to the next character which would be a letter, but I just can't work out the logic.

 

 

[Adam]

Ah.. You're missing a plus after \d, to mean 'match once or more'. That will effectively then match anything up to the next character which isn't a number.

[j.smith1981]

Finally my heads kicked in lol:

 

<?php
preg_match('/index.php\?cat=\d{1,}&post=\d{1,}/', 'index.php?cat=25&post=65', $matches);

 

{1,} means the character before the iteration must appear at least once but multiple times, anyways it works, tried even with {1,5} and deliberately entered 6 characters in the numeric part and it still works even, well not results come up but if I was to put in 6 using the {1,} then it would work.

 

Thanks for your help,

Jeremy.

[Adam]

Simpler syntax: \d+

[j.smith1981]

Sorry the last post I made does exactly the same thing I think really must try and get my brain working though but thank you so much is there any real difference though between the 2?

 

I suppose with the {} curly braces you could have a min set and the plus (+) would just say 1 or more (which I remember being the metachar for. Am I thinking in the right sense between + and {1,} ?

 

Finally understanding some rather simple but dynamic regexes really happy with what I am doing.

 

Really appreciate your help though!

Jeremy.

[Adam]

+ and {1,} mean exactly the same thing. * is also an alias of {0,} which means zero or more times. Your regular expression (no offence) is very simple, but when you move onto longer and more complex patterns they are a subtly large benefit. There's no need to use curly brackets unless you need to specify two or more times, three or more times, etc.