I have an array with numbers in it and want to loop through all combinations of them to calculate a minimum difference between the selected numbers and the rest. How would such a loop look like? I've tried to find a solution, but somehow it doesn't seem to be easy to find such a algorithm.
To solve your actual problem, i.e.
to calculate a minimum difference between the selected numbers and the rest
or in other words
to select numbers so that the sum of selected is nearest to half of the total sum
or in other words
a variation of the Knapsack problem
Now, you can do a quick search as there are various solutions there.