Re: Difficult String/number fomatation plz hlp!

Bobo Wieland <dev@elstudion.com> 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