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在C.NET 2.0中,反向做前臂的简单方法是什么?

iteration collections .net c#

Pandincus · 技术社区 · 18 年前

假设我有一个字典对象:

Dictionary myDictionary<int, SomeObject> = new Dictionary<string, SomeObject>();

现在我想按相反的顺序遍历字典。我不能使用简单的for循环,因为我不知道字典的键。一前额很容易:

foreach (SomeObject object in myDictionary.Values)
{
    // Do stuff to object
}

但我怎么能反向执行呢?

14 回复 | 直到 18 年前

Jonathan 18 年前

SortedList sCol = new SortedList();

sCol.Add("bee", "Some extended string matching bee");
sCol.Add("ay", "value matching ay");
sCol.Add("cee", "Just a standard cee");

// Go through it backwards.
for (int i = sCol.Count - 1; i >=0 ; i--)
    Console.WriteLine("sCol[" + i.ToString() + "] = " + sCol.GetByIndex(i));

// Reference By Key
foreach (string i in sCol.Keys)
    Console.WriteLine("sCol[" + i + "] = " + sCol[i]);

// Enumerate all values
foreach (string i in sCol.Values)
    Console.WriteLine(i);

leppie 18 年前

Peter Mortensen Pieter Jan Bonestroo 11 年前

foeach (SomeObject o in myDictionary.Values.Reverse())
{
     // Do stuff to object
}

Jason Plank Maksim Kondratyuk 14 年前

static IEnumerable<T> CreateReverseIterator<T>(IList<T> list)
{
    int count = list.Count;
    for (int i = count - 1; i >= 0; --i)
    {
        yield return list[i];
    }
}

static void Main(string[] args)
{
    Dictionary<int, string> dict = new Dictionary<int, string>();

    dict[1] = "value1";
    dict[2] = "value2";
    dict[3] = "value3";

    foreach (KeyValuePair<int, string> item in dict)
    {
        Console.WriteLine("Key : {0}, Value: {1}", new object[] { item.Key, item.Value });
    }

    string[] values = new string[dict.Values.Count];
    dict.Values.CopyTo(values, 0);

    foreach (string value in CreateReverseIterator(values))
    {
        Console.WriteLine("Value: {0}", value);
    }

}

OwenP 18 年前

foreach

for (int i = myCollection.Length - 1; i >= 0; i--)
{
    // do something
}

to StackOverflow 18 年前

public static IEnumerable<T> Reverse<T>(IEnumerable<T> items)
{
    IList<T> list = items as IList<T>;
    if (list == null) list = new List<T>(items);
    for (int i = list.Count - 1; i >= 0; i-- )
    {
        yield return list[i];
    }
}

Jason Plank Maksim Kondratyuk 14 年前

Dictionary<int, SomeObject> myDictionary

foreach(SomeObject _object in myDictionary.Values.Reverse())
{
}

Peter Mortensen Pieter Jan Bonestroo 11 年前

Dictionary<int, object> d;
List<object> tmplist;
foreach (object o in d.Values) tmplist.Add(s);
tmplist.Reverse();
foreach (object o in tmplist) {
    //Do stuff
}

Timothy Carter 18 年前

Gord 18 年前

here

Peter Mortensen Pieter Jan Bonestroo 11 年前

for

Peter Mortensen Pieter Jan Bonestroo 11 年前

LINQ to Objects LinqBridge

Peter Mortensen Pieter Jan Bonestroo 11 年前

Dictionary<int, SomeObject>  myDictionary = new Dictionary<int, SomeObject>();

foreach (var pair in myDictionary.OrderByDescending(i => i.Key))
{
    //Observe pair.Key
    //Do stuff to pair.Value
}

-2

Marvin 14 年前

foreach (Sample in Samples)

try the following:

Int32 nEndingSample = Samples.Count - 1;

for (i = nEndingSample; i >= 0; i--)
{
     x = Samples[i].x;
     y = Samples[i].y;
}