I have this string:
a:3:{i:0;i:2;i:1;i:3;i:2;i:4;}
I want to get number between "a:" and ":{" that is "3". I try to user substr and strpos but no success. I'm newbie in regex , write this :
preg_match('/a:(.+?):{/', $v);
But its return me 1. Thanks for any tips.
preg_match returns the number of matches, in your case 1 match.
To get the matches themselves, use the third parameter:
$matches = array();
preg_match(/'a:(\d+?):{/', $v, $matches);
That said, I think the string looks like a serialized array which you could deserialize with unserialize and then use count on the actual array (i.e. $a = count(unserialize($v));). Be careful with userprovided serialized strings though …
If you know that a: is always at the beginning of the string, the easiest way is:
$array = explode( ':', $string, 3 );
$number = $array[1];
You can use sscanfDocs to obtain the number from the string:
# Input:
$str = 'a:3:{i:0;i:2;i:1;i:3;i:2;i:4;}';
# Code:
sscanf($str, 'a:%d:', $number);
# Output:
echo $number; # 3
This is often more simple than using preg_match when you'd like to obtain a specific value from a string that follows a pattern.
preg_match() returns the number of times it finds a match, that's why. you need to add a third param. $matches in which it will store the matches.
You were not too far away with strpos() and substr()
$pos_start = strpos($str,'a:')+2;
$pos_end = strpos($str,':{')-2;
$result = substr($str,$pos_start,$pos_end);
preg_match only checks for appearance, it doesn't return any string.
a: Now it should be ok.
count()on the actual array?