生成两个字母数字值之间的范围

Question

I have a set of data where each item has a 'range from' and 'range to' string of varying types. For example the first item might have 3001A -> 4000A and the next item might be DE25500 -> DE27419 and so on (with several different patterns but usually consisting of a static section and a range section (it seems that usually any letter is static and numbers can either be static or not).

Is there any ready built function in PHP that can cope with generating the intermediate values in the range? Or if not any tips on how to build one?

Answer 1

I'm no PHP expert but couldnt you use a for loop for that.

You will need to extract the parts of your values that represent the ranges and then start the loop from the lowest to the highest.

$min = (int) substr("DE25500", 2)
$max = (int) substr("DE27419", 2)
for ($x = $min; $x <= $max; $x++) {
    // logic in here
}

Answer 2

I'd suggest you to first find all the patterns and then write functions that knows how to subdivide the numeric part from the litteral one. Then to work with ranges in PHP you can use http://php.net/range

Answer 3

Figured out a function to do this in the end...

function generateRange($startString, $endString, $step = 1)
{
    if (strlen($startString) !== strlen($endString)) {
        throw new LogicException('Strings must be equal in length');
    }

    // Get position of first character difference
    $position = mb_strlen(mb_strcut($startString, 0, strspn($startString ^ $endString, "\0")));
    if (!is_numeric($startString[$position]) || !is_numeric($endString[$position])) {
        throw new LogicException('The first character difference is not numeric');
    }

    // Get sequence
    $length = strspn($startString, '1234567890', $position);
    $prefix = substr($startString, 0, $position);
    $suffix = substr($startString, $position + $length);
    $start  = substr($startString, $position, $length);
    $end    = substr($endString, $position, $length);

    if ($start < $end) {
        if ($step <= 0) {
            throw new LogicException('Step must be positive');
        }
        for ($i = $start; $i <= $end; $i += $step) {
            yield $prefix . str_pad($i, $length, "0", STR_PAD_LEFT) . $suffix;
        }
    } else {
        if ($step >= 0) {
            throw new LogicException('Step must be negative');
        }
        for ($i = $start; $i >= $end; $i += $step) {
            yield $prefix . str_pad($i, $length, "0", STR_PAD_LEFT) . $suffix;
        }
    }
}

Only works when the ranges are equal length at the moment