Generate sequence of strings from array

Question

I have an alphabet array:

$ga = array_merge(range('A', 'Z'), range(0,9));

How can I generate next strings:

AAAA, AAAB... AAAZ, AAA0... AAA9, AABA, AA9A... ABAA... 9999

Thanks!

Answer 1

This probably is the easiest approach:

<?php
$alphabeth = array_merge(range('A', 'Z'), range(0,9));
$character = [];
foreach ($alphabeth as $character[0]) {
  foreach ($alphabeth as $character[1]) {
    foreach ($alphabeth as $character[2]) {
      foreach ($alphabeth as $character[3]) {
        $catalog[] = vsprintf('%s%s%s%s', $character);
      }
    }
  }
}
print_r($catalog);

The output obviously is:

Array
(
    [0] => AAAA
    [1] => AAAB
    [2] => AAAC
    [3] => AAAD
    .....
    [1679613] => 9997
    [1679614] => 9998
    [1679615] => 9999
)

---

UPDATE:

You mention in the comments below that you need to fill these strings into a file, if I got you right. If so, then this would be an example for a sequential processing which dramatically reduces the scripts memory footprint, as also mentioned in the comments:

<?php
$alphabeth = array_merge(range('A', 'Z'), range(0,9));
$handle = fopen('/home/arkascha/catalog.list', 'w');
foreach ($alphabeth as $character[0]) {
  foreach ($alphabeth as $character[1]) {
    foreach ($alphabeth as $character[2]) {
      foreach ($alphabeth as $character[3]) {
        fwrite($handle, vsprintf("%s%s%s%s\n", $character));
      }
    }
  }
}
fclose($handle);