Add a number in a List array

Question

I want to add a number to a List<double>[] distances = new List<double>[2];

for (int i = 0; i < 2; i++)
{
    for (int j = 0; j < 5; j++)
    {
         double distance = MyFunktionthatreturnsANumber();
         distances[i].Add(distance);
    }
}

But everytime I try to run this code i get this error at the first passage if the loop:

System.NullReferenceException: 'Object reference not set to an instance of an object.'

You have declared an array of two lists of double. You never initialized the two elements of that array. — GSerg, Dec 13 '20 at 18:09
For fun: `List[] distances = Enumerable.Range(0,2).Select(i => Enumerable.Range(0, 5).Select(j => MyFunktionthatreturnsANumber()).ToList()).ToArray();` — Joel Coehoorn, Dec 13 '20 at 18:24

score 2 · Accepted Answer · answered Dec 13 '20 at 18:08

You're declaring an array of List<double> objects, but you aren't initializing the elements of that array to an object?

List<double>[] distances = new List<double>[2];
distances[0] = new List<double>();
distances[1] = new List<double>();

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Add a number in a List array

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