在带有特殊字符的字符串中查找子字符串PHP

Question

I have a complex string like this

{},\"employees\":{},\"idIwant\":{\"2545\":{\"attributes\":{\"offset\":9855,

I need the sweet 2545 out from this string, I tried using regex, and strpos but it doesn't play nice with lots of colons, bracket, slashes. Is it possible to extract the number after idIwant ie 2545 ?

This is actually coming from a website's source code, and this is not a json but a redux state string.

Answer 1

Isolate the digits after the match like this:

Code: ( Demo )

$string = '{},\"employees\":{},\"idIwant\":{\"2545\":{\"attributes\":{\"offset\":9855,';

echo preg_match('~"idIwant\\\":{\\\"\K\d+~', $string, $out) ? $out[0] : 'bonk';

Output:

2545

Keeping the " and \\" around your sought key is important so that you are matching the whole targeted keyword (no inadvertent substring matching).

\\K restarts the fullstring match so that you don't need to bloat the output array with unnecessary elements.

Php requires 3 or 4 \\ to represent one in the pattern. (Here's some breakdown: https://stackoverflow.com/a/15369828/2943403 )

ps Alternatively, you can force the leading portion of the pattern to be literally interpretted with \\Q..\\E like this:

Demo

echo preg_match('~\Q\"idIwant\":{\"\E\K\d+~', $string, $out) ? $out[0] : 'bonk';

Or if you are scared off by so many metacharacters, you could reduce the stability of your pattern and just match the search string, then match one or more non-digits, then forget the previously matched characters, then match 1 or more digits:

echo preg_match('~idIwant\D+\K\d+~', $string, $out) ? $out[0] : 'bonk';

Answer 2

This will work if idIwant has only numbers.

$string = '{},\"employees\":{},\"idIwant\":{\"2545\":{\"attributes\":{\"offset\":9855,';

preg_match('/idIwant.*?(\d+)/', $string, $matches);

echo $matches[1];

Test

Answer 3

most easy way is:

$String ='{},\"employees\":{},\"idIwant\":{\"2545\":{\"attributes\":{\"offset\":9855,';

$arr1 = explode('"idIwant\":{\"', $String);

if you ouput $arr1[1] you would get:

string=> 2545\":{\"attributes\":{\"offset\":9855,';

you need:

$arr2 = explode('\":{\"', $arr1[1]);

and you would get on $arr2[0] :

string=> 2545

if the string have a strict syntax

Answer 4

There are so many ways to get that desired digits, one would be an expression similar to:

.+idIwant\\":{\\"(.+?)\\.+

Demo

Test

$re = '/.+idIwant\\\\":{\\\\"(.+?)\\\\.+/m';
$str = '{},\\"employees\\":{},\\"idIwant\\":{\\"2545\\":{\\"attributes\\":{\\"offset\\":9855,';
$subst = '$1';

$result = preg_replace($re, $subst, $str);

echo "The result of the substitution is ".$result;