I need a shorter way to compare variables? - php

Question

Okay I have 15 variables $A - $O. I need a different way to compare the variables as I think I am doing this a really long way. It works the way I want it to but I'm not happy with the amount of code.
So what my code is doing it's generating a random number for each of the variables. I have it doing this while they equal each other, so in other words it will stop generating random number when each of the variables is different here is my code... Thanks in advance.
do{
$a = rand($min,$max);
$b = rand($min,$max);
$c = rand($min,$max);
$d = rand($min,$max);
$e = rand($min,$max);
$f = rand($min,$max);
$g = rand($min,$max);
$h = rand($min,$max);
$i = rand($min,$max);
$j = rand($min,$max);
$k = rand($min,$max);
$l = rand($min,$max);
$m = rand($min,$max);
$n = rand($min,$max);
$o = rand($min,$max);
}
while ($a==$b || $a==$c || $a==$d || $a==$e || $a==$f || $a==$g || $a==$h || $a==$i || $a==$j || $a==$k || $a==$l || $a==$m || $a==$n || $a==$o
|| $b==$a || $b==$c || $b==$d || $b==$e || $b==$f || $b==$g || $b==$h || $b==$i || $b==$j || $b==$k || $b==$l || $b==$m || $b==$n || $b==$o
|| $c==$a || $c==$b || $c==$d || $c==$e || $c==$f || $c==$g || $c==$h || $c==$i || $c==$j || $c==$k || $c==$l || $c==$m || $c==$n || $c==$o
|| $d==$a || $d==$b || $d==$c || $d==$e || $d==$f || $d==$g || $d==$h || $d==$i || $d==$j || $d==$k || $d==$l || $d==$m || $d==$n || $d==$o
|| $e==$a || $e==$b || $e==$c || $e==$d || $e==$f || $e==$g || $e==$h || $e==$i || $e==$j || $e==$k || $e==$l || $e==$m || $e==$n || $e==$o
|| $f==$a || $f==$b || $f==$c || $f==$d || $f==$e || $f==$g || $f==$h || $f==$i || $f==$j || $f==$k || $f==$l || $f==$m || $f==$n || $f==$o
|| $g==$a || $g==$b || $g==$c || $g==$d || $g==$e || $g==$f || $g==$h || $g==$i || $g==$j || $g==$k || $g==$l || $g==$m || $g==$n || $g==$o
|| $h==$a || $h==$b || $h==$c || $h==$d || $h==$e || $h==$f || $h==$g || $h==$i || $h==$j || $h==$k || $h==$l || $h==$m || $h==$n || $h==$o
|| $i==$a || $i==$b || $i==$c || $i==$d || $i==$e || $i==$f || $i==$g || $i==$h || $i==$j || $i==$k || $i==$l || $i==$m || $i==$n || $i==$o
|| $j==$a || $j==$b || $j==$c || $j==$d || $j==$e || $j==$f || $j==$g || $j==$h || $j==$i || $j==$k || $j==$l || $j==$m || $j==$n || $j==$o
|| $k==$a || $k==$b || $k==$c || $k==$d || $k==$e || $k==$f || $k==$g || $k==$h || $k==$i || $k==$j || $k==$l || $k==$m || $k==$n || $k==$o
|| $l==$a || $l==$b || $l==$c || $l==$d || $l==$e || $l==$f || $l==$g || $l==$h || $l==$i || $l==$j || $l==$k || $l==$m || $l==$n || $l==$o
|| $m==$a || $m==$b || $m==$c || $m==$d || $m==$e || $m==$f || $m==$g || $m==$h || $m==$i || $m==$j || $m==$k || $m==$l || $m==$n || $m==$o
|| $n==$a || $n==$b || $n==$c || $n==$d || $n==$e || $n==$f || $n==$g || $n==$h || $n==$i || $n==$j || $n==$k || $n==$l || $n==$m || $n==$o
|| $o==$a || $o==$b || $o==$c || $o==$d || $o==$e || $o==$f || $o==$g || $o==$h || $o==$i || $o==$j || $o==$k || $o==$l || $o==$m || $o==$n
);

Answer 1

You could do this with an array:
$randoms = array();
while(count($randoms) < 15)
{
$randoms[] = mt_rand($min, $max);//add random
$randoms = array_unique($randoms);//remove duplicates
}
$randoms = array_combine(range('a', 'o'), $randoms);//set keys a to o
And if you really, Really want those values as separate variables, you can do this using variable variables:
foreach ($randoms as $letter => $val)
{
$$letter = $val;
}
Because I wrote $$letter (note two $ signs), this expression evaluates to $<value of $letter> or $a, $b and so on, to which I assign the corresponding value
I suppose, if you want to get the best performance for the least amount of code/overhead, this would be the way to get it:
$random = array();
$count = 0;
$rand = null;
while($count < 15)
{
$rand = mt_rand($min, $max);
if (!isset($random[$rand]))
{//assign random value, and use keys for faster lookup
++$count;
$random[$rand] = $rand;
}
}
var_dump($random);//guaranteed to hold 15 random values, both the keys and values
//so:
$vals = array_values($random);//or array_keys($random)
And again, to turn this array into a distinct variables:
$arr = array_combine(range('a', 'o'), array_values($random));
//or even array_combine(range('a', 'o'), $random);
foreach ($arr as $name => $val)
$$name = $val;

Answer 2

try this
$min = 0;
$min = 999;
while (count($array) < 16){
$val = rand($min,$max);
if (!in_array($val, $array)) {
$array[] = $val;
}
}

Answer 3

The easiest way is to add the variables to an array and then perform your do-while as such:
$arr = array(&$a, &$b, &$c, &$d);
do {
foreach ($arr as $i => $k)
$arr[$i] = rand($min, $max);
}
while (count($arr) == array_unique($arr));
But in your example you are re-doing a lot of work that is not needed, e.g do not re-random unique values. Just a tip.

Answer 4

In PHP you can use variables to access other variables by names in strings.
For instance you can do something like that in your case:
$names = array('a','b','c','d'); // And so on - it can be done easier with casting to char
function check_names_equal($names) {
foreach($names as $name) {
global $$name;
}
foreach($names as $name) {
foreach($names as $name2) {
if ($name != $name2 && $$name == $$name2) {
return true;
}
}
}
return false;
}
while(check_names_equal($names)); // <- this is your shortened while
My comment to that - I know it's not the perfect way to that and I would suggest that you use arrays for holding variables, don't store some random data in single variables.
Your start of the code should like like this prefferably: (it would better to use numbers as indexes too, so you can use loops)
$arr = array();
$arr['a'] = rand($min,$max);
$arr['b'] = rand($min,$max);
$arr['c'] = rand($min,$max);
$arr['d'] = rand($min,$max);
$arr['e'] = rand($min,$max);
$arr['f'] = rand($min,$max);
$arr['g'] = rand($min,$max);
$arr['h'] = rand($min,$max);
$arr['i'] = rand($min,$max);
$arr['j'] = rand($min,$max);
$arr['k'] = rand($min,$max);
$arr['l'] = rand($min,$max);
$arr['m'] = rand($min,$max);
$arr['n'] = rand($min,$max);
$arr['o'] = rand($min,$max);
And with numeric indexing:
$arr=array();
for($i = 0; $i < 10; $i++) {
$arr[] = rand($min,$max);
}

Answer 5

Ahother option is to create an array and go growing it with random values comparing every new vaue with the existing ones:
$myvars=array();
while (sizeof($myvars)<15)
{
$success=false;
do{
$candidate=rand($min,$max);
//compare the candidate with every element in array
if (!in_array($candidate, $myvars))
$success=true; //if found no success
} while (!$success);
$myvars[]=$candidate;
}
Now in $myvars you have 15 different values.