Random number from multiple ranges?

Question

PHP

I am interested in the implementation of the following moment,
for example, we have several numerical ranges
1-17
18-25
26-100
the range 18-25 for some reason fell out
how to implement the search for a random number from several ranges: 1-17, 26-100

Answer 1

$ranges = ;
$total = 0;
foreach ($ranges as $range)
  $total += $range[1]-$range[0]+1;
$rand = rand(0, $total-1);
foreach ($ranges as $range) {
  $rand += $range[0];
  if ($rand > $range[1])
    $rand -= $range[1]+1;
  else
    break;
}
echo $rand;

Answer 2

v = rand(1,100-8)
if v> 17 then v = v+8 you
get a uniform distribution regardless of the length of the ranges