PHP Regex preg_match_all

Question

I have a large text file that i need to remove a certain piece of information from, but i am still learning regular expressions and need some help with the search string statement.

Below is an example of the data i am trying to extract:

"id": "12345"  (good)
"id": "a123"   (bad)

The part i am having trouble with, is that i want to grab the first example, which has ONLY numbers as the value for ID. If there is a letter within the ID, i do not want to grab it. The ID numbers also differ in length, but the format is consistent:

"id": "number_here"

I have the following code but it does not seem to work for what i want to do:

preg_match_all("/\"id\"\:\s\"[0-9]\"/", $input_file)

Does this text file have any particular structure? It looks like it could be JSON — Explosion Pills
– Explosion Pills, Commented Apr 30, 2014 at 14:03

Niet the Dark Absol · Accepted Answer · 2014-04-30 14:02:38Z

4

Your regex is good (if a bit heavy on backslashes), except for one fatal flaw: You are only searching for a single digit.

preg_match_all('/"id": "[0-9]+"/', $input_file, $matches);
var_dump($matches);

Hope this helps!

answered Apr 30, 2014 at 14:02

Niet the Dark Absol

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2 Comments

user3569450 Over a year ago

worked like a charm! thank you very much!!! I was under the impression that all special chars had to be escaped.

Niet the Dark Absol Over a year ago

@user3569450 Heh, well there's certainly no harm in escaping things that don't really need it, but it's just a lot more readable to do this ;)

anubhava · Accepted Answer · 2014-04-30 14:02:31Z

2

You don't need to escape many characters in yiur regex
Use single quotes for regex
Make sure to use quantifier + to match 1 or more digits after "id":

You can use:

preg_match_all('/"id" *: *"[0-9]+"/', $input_string, $matches) ;

answered Apr 30, 2014 at 14:02

anubhava

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