PHP array combination with Left to Right order [duplicate]

问题

This question already has answers here:

Display possible combinations of string (3 answers)

Closed 4 years ago.

I have a PHP array that looks like this

$alphabet= array('a','b','c')

$alphabet is a input i need a result like $result

Expected output:

$result= array(
  [0]=> "a"
  [1]=> "b"
  [2]=> "c"
  [3]=> "ab"
  [4]=> "ac"
  [5]=> "bc"
  [6]=> "abc"
)

Note: here, I would not like sorting to use. Thanks!

回答1:

Use usort and costum sort function:

$array = array("a", "bc", "bb", "aa", "cc", "bb");

function sortByValueLength($a, $b)
{
    $aLength = mb_strlen($a, 'utf-8');
    $bLength = mb_strlen($b, 'utf-8');
    if ($aLength == $bLength) {
        return strcmp($a, $b);
    }

    return $aLength - $bLength;
}

usort($array, 'sortByValueLength');

var_export($array);

Example result here

来源：https://stackoverflow.com/questions/30368260/php-array-combination-with-left-to-right-order