C＃字典（顺序键）与Java SortedMap字典顺序

Question

I am using a SortedMap in Java and attempting to order a C# Dictionary by Keys. Comparing the outputs I would expect to see the same orders, however the orderings are different and I'm not sure why.

SortedMap<String, String> orderedByKey = new TreeMap<>();
orderedByKey.put("0:10", "");
orderedByKey.put("10:12+", "");
orderedByKey.put("2:10", "");
orderedByKey.put("1:10", "");
orderedByKey.put("10:1", "");

Dictionary<string, string> tmp = new Dictionary<string, string>();
tmp.Add("0:10", "");
tmp.Add("10:12+", "");
tmp.Add("2:10", "");
tmp.Add("1:10", "");
tmp.Add("10:1", "");
var orderedByKey = tmp.OrderBy(y => y.Key).ToDictionary(y => y.Key, y => y.Value);

Java orders them as follows...

0:10 10:1 10:12+ 1:10 2:10

C#

0:10 1:10 10:1 10:12+ 2:10

The line I was thinking down here was that my C# ordering had ordered the Dictionary but using a different precedent to Java ie C# considers ':' before '0' and in Java '0' is before ':'.

Answer 1

The issue here is that in C#, String.CompareTo takes culture into account by default, which provides a slightly different result than Java's String.compareTo method, which uses pure lexicographical comparison.

If you want the C# string comparison to behave like Java, then we can simply specify StringComparer.Ordinal as the comparison type, which compares just the ordinal position of each character:

private static void Main()
{
    Dictionary<string, string> tmp = new Dictionary<string, string>
    {
        {"0:10", ""},
        {"10:12+", ""},
        {"2:10", ""},
        {"1:10", ""},
        {"10:1", ""}
    };

    var javaSorted = tmp.OrderBy(item => item.Key, StringComparer.Ordinal)
        .ToDictionary(i => i.Key, i => i.Value);

    Console.WriteLine(string.Join(", ", javaSorted.Select(item => item.Key)));

    GetKeyFromUser("\nDone! Press any key to exit...");
}

Output

Answer 2

可能您正在寻找SortedDictionary<TKey,TValue> ，它表示按键排序的键/值对的集合。