I'm creating a script which creates a random security number for a user, and I'm looking at ways I can complete this.
I need a security number with 7 digits but doesn't contain a 0. but when using rand(1111111,9999999) there is still a possibility of a 0 being inside of that number, I was wondering which loop would be best to check this and what function would I use to check for the existence of a 0 in the string?
This code should do what you need:
$num = '';
for ($i = 1; $i <= 7; $i++)
$num .= rand(1, 9);
$num = (int) $num;
It randomly generates the digits one by one and builds a string with them. Then, it changes the string to an integer.
Couldn't you concat a random number between 1 and 9 7 times?
rand(1,9)
Using while to check will not help as there will be total 9^7 cases. You don't know which case you will get next time. So better to use rand 7 times.
<?php
function myRand($length){
$ans=0;
for($i=0;$i<$length;$i++){
$ans=$ans*10+rand(1,9);
}
return $ans;
}
echo myrand(7);
?>
Solution based on base 9.
$p = array();
$p[0] = 1;
for ($i=1; $i<=6; $i++):
$p[$i] = $p[$i-1] * 9;
endfor;
$max = $p[6] * 9 - 1;
$rand = rand(0,$max);
$ret = array();
for ($i=6; $i>=0; $i--):
$tmp = $rand / $p[$i];
$tmp = floor($tmp);
$rand = $rand - $p[$i] * $tmp;
$ret[] = (string)($tmp + 1);
var_dump($tmp);
endfor;
$ret = implode($ret);
var_dump($ret);
