adding items to a list in a dictionary

c#, dictionary, list

Solution

You are using the same list for both keys in the Dictionary

    for (int index = 0; index < 5; index++)
    {
        if (testList.ContainsKey(key[index]))
        {
            testList[k].Add(val[index]);
        }
        else
        {
            testList.Add(key[index], new List<long>{val[index]});
        }
    }

Just create one new List(Of Long) when the key doesn't exists then add the long value to it

Problem

I'm trying to put values into a dictionary dependent on the key... For example, if in a list of keys at the index 0 there is a letter "a". I want to add the val with index 0 to a list inside of a dictionary with the key "a" ( dictionary (key is "a" at index 0 , val at index 0) ... dictionary (key is "b" at index 2 , val at index 2)) I'm expecting an output like this: in listview lv1: 1,2,4 in listview lv2: 3,5 what I'm getting is 3,4,5 in both listviews ``` List<string> key = new List<string>(); List<long> val = new List<long>(); List<long> tempList = new List<long>(); Dictionary<string, List<long>> testList = new Dictionary<string, List<long>>(); key.Add("a"); key.Add("a"); key.Add("b"); key.Add("a"); key.Add("b"); val.Add(1); val.Add(2); val.Add(3); val.Add(4); val.Add(5); for (int index = 0; index < 5; index++) { if (testList.ContainsKey(key[index])) { testList[key[index]].Add(val[index]); } else { tempList.Clear(); tempList.Add(val[index]); testList.Add(key[index], tempList); } } lv1.ItemsSource = testList["a"]; lv2.ItemsSource = testList["b"]; ``` Solution: replace the else code section with : testList.Add(key[index], new List { val[index] }); thx everybody for your help =)

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