CODEWITHSUNDEEP
c#linq
user2483744
user2483744

Reputation: 303

LINQ RemoveAll instead of loops

I have two for loops to remove item from the list. I am looking for an equivalent LINQ statement for these loops

for (Int32 i = points.Count - 1; i >= 0; i--)
{
    for (Int32 j = touchingRects.Count - 1; j >= 0; j--)
    {
        if (touchingRects[j].HitTest(points[i], rect.TopEdge.Y1))
        {
            points.RemoveAt(i);
        }
    }
}

So far I am able to do this but the compiler doesn't understand this code:

points.RemoveAll(p => touchingRects.Where(r => r.HitTest(p, r.TopEdge.Y1)));

Any help will be appreciated.

Upvotes: 2

Views: 183

Answers (1)

p.s.w.g
p.s.w.g

Reputation: 149000

The delegate that you pass into RemoveAll needs to return a bool.

I think you what to do this:

points.RemoveAll(p => touchingRects.Any(r => r.HitTest(p, r.TopEdge.Y1)));

Or possibly this (if the variable rect is actually defined elsewhere):

points.RemoveAll(p => touchingRects.Any(r => r.HitTest(p, rect.TopEdge.Y1)));

I should point out that your original code has the potential for some very strange behavior. After you remove an item from the list in your inner loop, you continue looping through touchingRects with the same index i. This can lead to some unexpected results. There probably should be a break in there somewhere, but you may have omitted from your question it for brevity. In any case, using this code fixes that problem.

Upvotes: 6

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