Question

I have a text file, and I need to pick a random string that is over 6 characters and under 10 characters. Normally, I would use a script like this, which would work, but since it needs to be a certain length, that won’t work. Does anybody have a solution to this?

A sample input would be something like this:

Apple
Banana
Orange
Strawberry
Blueberry
Pineapple
Somelongfruithere

Those values would be in a .txt file, each with a line break. An example of a string that would be allowed is pineapple, but apple or Somelongfruithere wouldn’t be allowed.

Answer 1

You’ll need to do something like this:

$lines = array();
$tmpLines = file('random.txt');
for($i = 0; $i < count($tmpLines); ++$i)
{
    if(strlen($tmpLines[ $i ]) > 6 && strlen($tmpLines[ $i ]) < 10)
    {
        $lines[] = $tmpLines[ $i ];
    }
}
$randomWord = $lines[ array_rand($lines) ];

A shorter way, in number of lines, goes like this (but is much less safe):

$randomWord = '';
$lines = file('random.txt');
while(strlen($randomWord) <= 6 || strlen($randomWord) >= 10)
    $randomWord = $lines[ array_rand($lines) ];

The first option gets all the lines in the file, and copies only the ones between 6 and 10 chars in length to another array. When choosing a random element from this array, you are “guaranteed” a reasonable access time for any random string.

The second option simply continues to pick a random string until one of the proper length is chosen, but could potentially take a while depending on the random number generator’s mood. Unlikely, but I wouldn’t want to risk it. Always take reliability as the best approach, in my book.