Sum Identical Members of an Array

[libero30]

Hello,

I have a 2-dimensional array:
(not in my actual written code)

alpha[x][y]

I need to sum the 'y' values each time that the 'x' values associated with them are the same. The 'x' values will be doubles with up to 3 decimal places. I then need to output this as another array, preferably in order of size. Is there an easy way to do this?

Thanks in advance for any help.

[weaknessforcats]

I'm sorry, but your problem sounds confusing to me.

Do you mean to compare elements like alpha[2][3] with alpha[2][4] to see of they are equal??

I don't understand what you mean by 'y' values anmd 'x' values.

[libero30]

Sorry if I didn't make it clear. If for an array I have:

alpha[x][y]= {{1, 12},
{2, 6},
{3, 5},
{2, 5},
{1, 15}}

I want to to sum the second number (y), if the numbers in the first array (x) match.

For example from the array above, the number 1 occurs more than once so I want to have a new array with 12+15. I really want to end up with something like this for the above example:

alpha[x][y]={{1, 27},
{2, 11},
{3, 5}}

Although in my program there are more than a million doubles, instead of integers.

I hope this is more clear. The code above is just an example, not what is written in my program.

Thanks

[Raghunandan24]

You could sort the array initially using the i values of array[i][j]. Then add the numbers.

Another option could be run 1 loop say 'x' from 0 to length of array-1. Inside this loop run another loop say 'y' from x to length of array. You could check if the values of array[x][0] and array[y][0] are the same and add the values.
Hope this helps.