How to make a choice based on a percentage probability

c#, probability

Solution

To use your probability, compare it with a sample from random variable following a uniform distribution on `[0, 1]`.

if (Random.NextDouble() <= probability)
    // Take the ith element in the list

You resulting loop will be:

List<???> selectedItems = new List<???>();
for (var i = 0; i < remainingIndices.Count; i++)
{
    var probability = pixelsToAdd / (float)(remainingIndices.Count - i);
    if (Random.NextDouble() <= probability)
    {
        selectedItems.Add(items[i]);
        pixelsToAdd--;
    }
}

Problem

I wish to use the answer provided in this post to randomly choose unique items from a list. Following the method described, in each iteration of my loop I generate a probability value which is the percentage chance of the current item being picked from the list. What I need to know is how do I use this percentage value to pick the item (or not). Here is the code I have, with `remainingIndices` being a `List<int>` ``` for (var i = 0; i < remainingIndices.Count; i++) { var probability = pixelsToAdd / (float)(remainingIndices.Count - i); } ``` `pixelsToAdd` is 120 and `remainingIndices.Count` is 3600. The probability values I am getting start at 0.0333333351 The solution should be flexible to work with a much wider range of values, preferably any values. Thanks Comment For future readers of this question I should clarify that at first I thought the probability value was some percentage between 0 and 100 but in reality it's a value between 0 and 1 and so matches up perfectly with the return value of `Random.NextDouble()` which therefore can be used for comparison as described in the answers below.

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