How to get all possible combinations of elements in an array, including order and length
Gitu
function getAllCombinations(arr) {
var f = function(arr) {
var result = [];
var temp = [];
for (var i = 0; i < arr.length; i++) {
temp = [];
temp.push(arr[i]);
result.push(temp);
for (var j = 0; j < arr.length; j++) {
if (j != i) {
temp = [];
temp.push(arr[i]);
temp.push(arr[j]);
result.push(temp);
for (var k = 0; k < arr.length; k++) {
if (k != i && k != j) {
temp = [];
temp.push(arr[i]);
temp.push(arr[j]);
temp.push(arr[k]);
result.push(temp);
for (var l = 0; l < arr.length; l++) {
if (l != i && l != j && l != k) {
temp = [];
temp.push(arr[i]);
temp.push(arr[j]);
temp.push(arr[k]);
temp.push(arr[l]);
result.push(temp);
}
}
}
}
}
}
}
return result;
}
return f(arr);
}
//call this function
console.log(getAllCombinations(["a", "b", "c", "d"]));[["a"],["a","b"],["a","b","c"],["a","b","c","d"],["a","b","d"],["a","b","d","c"],["a","c"],["a","c","b"],["a","c","b","d"],["a","c","d"],["a","c","d","b"],["a","d"],["a","d","b"],["a","d","b","c"],["a","d","c"],["a","d","c","b"],["b"],["b","a"],["b","a","c"],["b","a","c","d"],["b","a","d"],["b","a","d","c"],["b","c"],["b","c","a"],["b","c","a","d"],["b","c","d"],["b","c","d","a"],["b","d"],["b","d","a"],["b","d","a","c"],["b","d","c"],["b","d","c","a"],["c"],["c","a"],["c","a","b"],["c","a","b","d"],["c","a","d"],["c","a","d","b"],["c","b"],["c","b","a"],["c","b","a","d"],["c","b","d"],["c","b","d","a"],["c","d"],["c","d","a"],["c","d","a","b"],["c","d","b"],["c","d","b","a"],["d"],["d","a"],["d","a","b"],["d","a","b","c"],["d","a","c"],["d","a","c","b"],["d","b"],["d","b","a"],["d","b","a","c"],["d","b","c"],["d","b","c","a"],["d","c"],["d","c","a"],["d","c","a","b"],["d","c","b"],["d","c","b","a"]]A total of 64 combinations of 4 length arrays.
The function works fine, but I need to make the function recursive. The for loops must be nested based on the length of the array, and the push for each nested loop will also increase.
Really appreciate some suggestions.
Gitu
Finally made it recursive! Tried to work on the original code posted above, converting each loop function into a simple function.
function getAllCombinations(inputArray) {
var resultArray = [];
var combine = function() {
for (var i in inputArray) {
var temp = [];
var tempResult = [];
for (var j in arguments) {
tempResult.push(inputArray[arguments[j]]);
if (arguments[j] == i) {
temp = false;
} else if (temp) {
temp.push(arguments[j]);
}
}
if (temp) {
temp.push(i);
combine.apply(null, temp);
}
}
if (tempResult.length > 0) {
resultArray.push(tempResult);
}
return resultArray;
};
return combine();
}Check out the old version here .
The result generates 64 unique combinations for a 4-dimensional array
console.log(getAllCombinations(["a", "b", "c", "d"]));[["a","b","c","d"],["a","b","c"],["a","b","d","c"],["a","b","d"],["a","b"],["a","c","b","d"],["a","c","b"],["a","c","d","b"],["a","c","d"],["a","c"],["a","d","b","c"],["a","d","b"],["a","d","c","b"],["a","d","c"],["a","d"],["a"],["b","a","c","d"],["b","a","c"],["b","a","d","c"],["b","a","d"],["b","a"],["b","c","a","d"],["b","c","a"],["b","c","d","a"],["b","c","d"],["b","c"],["b","d","a","c"],["b","d","a"],["b","d","c","a"],["b","d","c"],["b","d"],["b"],["c","a","b","d"],["c","a","b"],["c","a","d","b"],["c","a","d"],["c","a"],["c","b","a","d"],["c","b","a"],["c","b","d","a"],["c","b","d"],["c","b"],["c","d","a","b"],["c","d","a"],["c","d","b","a"],["c","d","b"],["c","d"],["c"],["d","a","b","c"],["d","a","b"],["d","a","c","b"],["d","a","c"],["d","a"],["d","b","a","c"],["d","b","a"],["d","b","c","a"],["d","b","c"],["d","b"],["d","c","a","b"],["d","c","a"],["d","c","b","a"],["d","c","b"],["d","c"],["d"]]