« Posts tagged pivot table

Pivot algorithm

So today at work, I needed to write a function to create a “pivot table”, given an arbitrary number of dimensions. With a defined number of dimensions, this was easy, but making it generic took some thinking. Here’s how I solved it:

* Given a set of sets, this function will return all the combinations
* of those sets. For instance, say a shirt comes in sizes S, M, and L,
* and colors Black and White, and can be labeled with either Mom or Dad,
* this will return an array of arrays with the following:
* {
* {S, Black, Mom}
* {S, Black, Dad}
* {S, White, Mom}
* {S, White, Dad}
* {M, Black, Mom}
* …
* }
* The function can accept any number of sets to combine.
function pivot(array){
if(array.length == 1){
var bottom = new Array();
for(var i = 0; i < array[0].length; i++){ bottom.push(new Array(array[0][i].toString())); } return bottom; } else { var myPivot = pivot(array.slice(1)); var newArray = new Array(); for(var i = 0; i < array[0].length; i++){ for(var j = 0; j < myPivot.length; j++){ var tempArray = myPivot[j].slice(); tempArray.unshift(array[0][i].toString()); newArray.push(tempArray); } } return newArray; } } [/javascript]