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How to use SkipWhile() to skip duplicate elements in two arrays?

I am trying to get a list of numbers (upto 9) that don't contain any numbers already in a 3x3 cell from which is contained within a 81 large 2d array of integers. I'm attempting to make sudoku. There are likely better solutions that have nothing to with skipwhile or something similar, but they all seem to rely on duplicate numbers having the same index in both array which doesn't work.

int[] inCellNumbers = thisCell.Intersect(Numbers).ToArray();
int[] availableNumbers = Numbers.SkipWhile(Numbers.Contains<int>(inCellNumbers) == true);

This is the code that I tried, numbers is an array of integers and I get this error:

'MemoryExtensions.Contains(ReadOnlySpan, int)' requires a receiver of type 'ReadOnlySpan'

I was attempting to skip all numbers that are in 'inCellNumbers' and have them in 'availableNumbers' from 'Numbers'

Solution

  • You can use the Enumerable.Except Method:

    int[] availableNumbers = Numbers.Except(inCellNumbers).ToArray();

    The Enumerable.SkipWhile Method stops skipping at the first element that does not fulfill the condition. Even if others follow later that do fulfill it.