Question

我必须列出4个字符A-Z，a-z，0-9的所有可能的限制以及所有这些的组合。我如何通过所有可能的组合并打印它们？

它的用途是什么：我需要在一个html文档中创建它，然后我可以打印并将所有这些作为我们大学的随机唯一用户名，这样学生就可以根据一个在使用时无效的唯一ID提供反馈。我无法将此程序改为更好的程序！

Answer 1

警告：这需要一些时间来计算，因为有62 ^ 4 = 14776336种可能的组合。如果累积结果并且不直接打印它也会占用大量内存。

function print_combinations($characters, $length, $combination = '') {
        if ($length > 0) {
            foreach ($characters as $i) {
                print_combinations($characters, $length - 1, $combination . $i);
            }
        } else {
            printf("%s\n", $combination);
        }
}

$characters = array_merge(range('A', 'Z'), range('a', 'z'), range(0, 9));
print_combinations($characters, 4);

Answer 2

使用非常规方法，您可以使用comments on the php documentation for base_convert中的dec2any，如下所示：

$index = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
$base = strlen($index);
$len = 4;

for ($i = 0, $l = pow(strlen($index), $len); $i < $l; $i++) {
    echo str_pad(dec2any($i, $base, $index), $len, "0", STR_PAD_LEFT), "\n";
} 

function dec2any( $num, $base=62, $index=false ) {
    if (! $base ) {
        $base = strlen( $index );
    } else if (! $index ) {
        $index = substr( "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" ,0 ,$base );
    }
    $out = "";
    for ( $t = floor( log10( $num ) / log10( $base ) ); $t >= 0; $t-- ) {
        $a = floor( $num / pow( $base, $t ) );
        $out = $out . substr( $index, $a, 1 );
        $num = $num - ( $a * pow( $base, $t ) );
    }
    return $out;
}

通过更改$ index和$ len可以很容易地进行调整。

Answer 3

有点匆忙，但是：

class Combinations{

    protected $characters = array();
    protected $combinations = array();

    public function __construct($characters){
        $this->characters = $characters;
    }

    public function getCombinations($length){       

        foreach($this->characters as $comb)
        {
            $this->getRecurse($comb, $length - 1);
        }

    $combinations = $this->combinations;
    $this->combinations = array();

    return $combinations;

    }

    public function getRecurse($combination, $length){

        if($length <= 0){
            $this->combinations[] = $combination;
        }else{
            foreach($this->characters as $comb)
            {
                $this->getRecurse($combination.$comb, $length - 1);
            }
        }

    }

}

$characters = array_merge(range('A', 'Z'), range('a', 'z'), range(0, 9));

$comb = new Combinations($characters);

print_r( $comb->getCombinations(4) );

传递给getCombinations的数字是您希望组合的时长。

Answer 4

更具普遍性的分隔符方法：

function getCombinations($base,$delimiter="|"){

    $base = array_values($base);
    $baselen = count($base);

    if($baselen == 0){
        return;
    }
    if($baselen == 1){
        return $base[0];
    }else{
        //get one level lower combinations
        $oneLevelLowerArray = $base;
        $orig_part = $oneLevelLowerArray[0];
        unset($oneLevelLowerArray[0]);
        $oneLevelLower = getCombinations($oneLevelLowerArray,$delimiter);
        $countOLL = count($oneLevelLower);
        foreach ($orig_part as $rowa) {
            foreach ($oneLevelLower as $rowb) {
                $resultArray[] = $rowa.$delimiter.$rowb;
            }
        }

    }

    return $resultArray;


}

Answer 5

那样的东西？（伪代码）

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

foreach($a as $key => $b) {
    echo $b.$a[$key+1].$a[$key+2].$a[$key+3].'<br />';
}

Answer 6

$numbers = range(0, 9);
$lowerCaseLetters = range('a', 'z');
$upperCaseLetters = range('A', 'Z');

foreach($numbers as $number) {
   foreach($lowerCaseLetters as $lowerCaseLetter) {
      foreach($uperCaseLetters as $upperCaseLetter) {
          echo $number.$lowerCaseLetter.$upperCaseLetter.'<br />';
          echo $number.$upperCaseLetter.$lowerCaseLetter.'<br />';
          echo $lowerCaseLetter.$number.$upperCaseLetter.'<br />';
          echo $lowerCaseLetter.$upperCaseLetter.$number.'<br />';
          echo $upperCaseLetter.$lowerCaseLetter.$number.'<br />';
          echo $upperCaseLetter.$number.$lowerCaseLetter.'<br />';
      }
   }
}

PHP制作4char A-Z，a-z，0-9的所有可能变种

6 个答案: