Bobo Wieland <[EMAIL PROTECTED]> wrote:
> I have a textfield wich allows any number of integers seperated with
> " ", "," or "-"...
>
> I need this input to be formated in two steps:
> First into a sequence of numbers into an array, lowest first...
> Second to the correct form of the initial input...
>
> Example:
>
> User input: "1,3, 3-6, 8" (string)
> First step: 1,3,4,5,6,8 (array)
> second step: "1,3-6,8" (string)
There are many ways to do this (as always :) ...
Do you really need the fully expanded array in step one, considering
it might get quite big?
Anyway, you can easily replace input ranges by expanded enumerations
with preg_replace:
$input = preg_replace('= (\d+) \s* - \s* (\d+) =ex',
'implode(",", range($1,$2))',
$input);
>From there, next step is to transform this list of numbers into an array
and normalize it, eliminating duplicates and sorting.
If you're really dealing with integers only, a funny and efficient way
to eliminate duplicates is to flip the array, because any array key can
exist only once:
$keys = array_keys( array_flip( split('[ ,]+', $input) ) );
sort($keys);
For the second step, merging consecutive numbers into a range, just do
what you would do with paper and pencil: start with first number,
step to next one and look, if it belongs to the previous range or starts
a new one. Write a dash only for real ranges with more than a single
number:
$start = $old = $keys[0]; $output = "$start";
foreach($keys as $value) {
if ($value > $old+1) // new range begins
{
if ($old<>$start) { $output .= "-$old"; }
$start = $value; $output .= ",$start";
}
$old = $value;
}
if ($old<>$start) { $output .= "-$old"; }
HTH,
Martin
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