Loop a 2 letter range

问题

I'm trying to achieve a loop over all possible 2 letter combinations. Something like

foreach(range(aa,zz) as $i) {...}

My current solution is:

foreach (range(a, z) as $first) {
    foreach (range(a, z) as $second) {
        //all 2 letter combinations
        echo $first.$second;
    }
}

This makes me worry that if I needed all possible 10 letter combinations, there would be 10 loops involved.

Is there a better way to achieve this?

回答1:

You could loop over letters using a simple for loop :

for ($letter = 'aa'; $letter != 'aaa'; ++$letter) {
  echo $letter . '<br>';
}

Output :

aa
ab
...
zy
zz

回答2:

$a = array(1,2,3,4,5,6,7,8,9,0);
$b = array('q','r','s','t','u','v','w','x','y','z');
for($i = 26;$i <= 1000;$i++)
    echo str_replace($a,$b,base_convert ( $i, 10 , 26))."<br />";

just put in the right starting and end positions.

来源：https://stackoverflow.com/questions/25687913/loop-a-2-letter-range