获取数字的类似Excel的列名的算法

Question

我正在编写一个生成一些Excel文档的脚本,我需要将一个数字转换为其等效的列名.例如:

1 => A
2 => B
27 => AA
28 => AB
14558 => UMX

我已经编写了一个算法来做这个,但我想知道是否更简单或更快的方法:

function numberToColumnName($number){
    $abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $abc_len = strlen($abc);

    $result_len = 1; // how much characters the column's name will have
    $pow = 0;
    while( ( $pow += pow($abc_len, $result_len) ) < $number ){
        $result_len++;
    }

    $result = "";
    $next = false;
    // add each character to the result...
    for($i = 1; $i<=$result_len; $i++){
        $index = ($number % $abc_len) - 1; // calculate the module

        // sometimes the index should be decreased by 1
        if( $next || $next = false ){
            $index--;
        }

        // this is the point that will be calculated in the next iteration
        $number = floor($number / strlen($abc));

        // if the index is negative, convert it to positive
        if( $next = ($index < 0) ) {
            $index = $abc_len + $index;
        }

        $result = $abc[$index].$result; // concatenate the letter
    }
    return $result;
}

你知道更好的方法吗？也许是为了让它更简单？还是性能提升？

编辑

ircmaxell的实现工作得很好.但是,我要添加这个不错的短文:

function num2alpha($n)
{
    for($r = ""; $n >= 0; $n = intval($n / 26) - 1)
        $r = chr($n%26 + 0x41) . $r;
    return $r;
}

Answer 1

这是一个很好的简单递归函数(基于零索引数,意味着0 == A,1 == B等)......

function getNameFromNumber($num) {
    $numeric = $num % 26;
    $letter = chr(65 + $numeric);
    $num2 = intval($num / 26);
    if ($num2 > 0) {
        return getNameFromNumber($num2 - 1) . $letter;
    } else {
        return $letter;
    }
}

如果你想要一个索引(1 == A,等):

function getNameFromNumber($num) {
    $numeric = ($num - 1) % 26;
    $letter = chr(65 + $numeric);
    $num2 = intval(($num - 1) / 26);
    if ($num2 > 0) {
        return getNameFromNumber($num2) . $letter;
    } else {
        return $letter;
    }
}

测试从0到10000的数字......

Answer 2

使用PhpSpreadsheet(不推荐使用PHPExcel)

// result = 'A'
\PhpOffice\PhpSpreadsheet\Cell\Coordinate::stringFromColumnIndex(1);

注意索引0导致'Z'

https://phpspreadsheet.readthedocs.io/en/develop/

正确答案(如果您使用PHPExcel Library)是:

// result = 'A'
$columnLetter = PHPExcel_Cell::stringFromColumnIndex(0); // ZERO-based! 

和倒退:

// result = 1
$colIndex = PHPExcel_Cell::columnIndexFromString('A');

Answer 3

索引为1 - > A,2 - > B等

function numToExcelAlpha($n) {
    $r = 'A';
    while ($n-- > 1) {
        $r++;
    }
    return $r;
}

索引为0 - > A,1 - > B等

function numToExcelAlpha($n) {
    $r = 'A';
    while ($n-- >= 1) {
        $r++;
    }
    return $r;
}

利用PHP在处理字符变量而不是C的算术运算时遵循Perl的约定这一事实.请注意,字符变量可以递增但不递减.

Answer 4

数字转换为 Excel 列字母：

\n\n

/**\n * Number convert to Excel column letters\n * \n * 1 = A\n * 2 = B\n * 3 = C\n * 27 = AA\n * 1234567789 = CYWOQRM\n * \n * @link https://vector.cool/php-number-convert-to-excel-column-letters-2\n * \n * @param int  $num       \xe6\xac\x84\xe6\x95\xb8\n * @param bool $uppercase \xe5\xa4\xa7\xe5\xb0\x8f\xe5\xaf\xab\n * @return void\n */\nfunction num_to_letters($n)\n{\n    $n -= 1;\n    for ($r = ""; $n >= 0; $n = intval($n / 26) - 1)\n        $r = chr($n % 26 + 0x41) . $r;\n    return $r;\n}\n

\n\n

前任：

\n\n

echo num_to_letters(1);          // A\necho num_to_letters(2);          // B\necho num_to_letters(3);          // C\necho num_to_letters(27);         // AA\necho num_to_letters(1234567789); // CYWOQRM\n

\n\n

Excel 列字母转换为数字：

\n\n

/**\n * Excel column letters convert to Number\n *\n * A = 1\n * B = 2\n * C = 3\n * AA = 27\n * CYWOQRM = 1234567789\n * \n * @link https://vector.cool/php-number-convert-to-excel-column-letters-2\n * \n * @param string $letters\n * @return mixed\n */\nfunction letters_to_num($a)\n{\n    $l = strlen($a);\n    $n = 0;\n    for ($i = 0; $i < $l; $i++)\n        $n = $n * 26 + ord($a[$i]) - 0x40;\n    return $n;\n}\n

\n\n

前任：

\n\n

echo letters_to_num(\'A\');       // 1\necho letters_to_num(\'B\');       // 2\necho letters_to_num(\'C\');       // 3\necho letters_to_num(\'AA\');      // 27\necho letters_to_num(\'CYWOQRM\'); // 1234567789\n

\n

Answer 5

这将完成转换（假定为整数算术），但是我同意其他说法。只是使用base_convert

function numberToColumnName($number)
{
    $abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $len = strlen($abc);

    $result = "";
    while ($number > 0) {
       $index  = $number % $len;
       $result = $abc[$index] . $result;
       $number = floor($number / $len);
    }

    return $result;
}

Answer 6

迟到的答案，但这是我所做的（对于 1==A 索引）：

function num_to_letters($num, $uppercase = true) {
    $letters = '';
    while ($num > 0) {
        $code = ($num % 26 == 0) ? 26 : $num % 26;
        $letters .= chr($code + 64);
        $num = ($num - $code) / 26;
    }
    return ($uppercase) ? strtoupper(strrev($letters)) : strrev($letters);
}

然后，如果您想以其他方式转换：

function letters_to_num($letters) {
    $num = 0;
    $arr = array_reverse(str_split($letters));

    for ($i = 0; $i < count($arr); $i++) {
        $num += (ord(strtolower($arr[$i])) - 96) * (pow(26,$i));
    }
    return $num;
}