Search code examples
phpregexstringpreg-matchdigits

How to get all the digits at the beginning of a string?

How can I get all the digits at the beginning of a string?

Here is an example string: 1&days=800&trans=9aq8ojjfka24qnl10ohktibfs1

In the example above, I would need to extract 1.

Solution

  • If you need the leading digits - including mulitple zeros - you can scan the string for it. If none exists, the value will be NULL:

    $subject = '1&days=800&trans=9aq8ojjfka24qnl10ohktibfs1';   

sscanf($subject, '%[0-9]', $leadingDigits);

echo 'Leading digits are: ', var_dump($leadingDigits);

    Outpupt (Demo):

    Leading digits are: string(1) "1"

    If you do not need leading zeroes, do what vascowhite suggested, that is pretty straight forward. Otherwise:

    sscanf($subject, '%d', $leadingDigits);

    Returns an integer, too.