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How to get long 19 digits of random numbers in PHP?

Therefore, I need to make a unique mobile game purchase number. Each user who buys a position record in the application must be bound with unique long 19 digit numbers from the php code and stored in the mysql DB.

But how can I actually make the random 19 digits?

I tried like this but errors.

$num_str = sprintf("%19d", mt_rand(1, 9999999999999999999));
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3 answers


you can also try this:

function random19() {
  $number = "";
  for($i=0; $i<19; $i++) {
    $min = ($i == 0) ? 1:0;
    $number .= mt_rand($min,9);
  }
  return $number;
}

echo random19();


which outputs some random 19 numbers: 6416113158912395605

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You should do something like:

$num_str = sprintf("%10d", mt_rand(1, mt_getrandmax())).sprintf("%9d", mt_rand(1, mt_getrandmax()));
if (strlen($num_str) < 19)
    $num_str = str_pad($num_str, 19, rand(0, 9), STR_PAD_RIGHT);
else if(strlen($num_str) > 19)
    $num_str = substr($num_str, 0, 19);
echo $num_str;


The distribution of mt_rand () return values ​​shifts towards even numbers in 64-bit PHP builds when max exceeds 2 ^ 32. This is because if max is greater than the value returned by mt_getrandmax (), the output of the random number generator must be incremented.

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$ randNumber = date ("YmdHis"). rand (11111.99999);

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