从list< object>的列表中删除重复的内部列表.在C#中 [英] Remove duplicate inner lists from a list of list<object> in c#

问题描述

我为模糊的标题表示歉意.我不能同时保持简洁明了.因此，请随时进行更改.

I apologize for the ambiguous title. I couldn't keep it clear and concise at the same time. So feel free to change it.

我有一个很大的列表，其中包含其他几个列表.这些内部列表包含Column对象.

I have a big List which contains several other Lists. And these inner Lists contain Column objects.

List<List<Column>> listOfAllColumns;

假设我的内部列表包含不同的Column对象，如下所示:

Let's say my inner lists contain different Column objects like this:

list1 = {c1, c1, c2}
list2 = {c1, c2, c1}
list3 = {c2, c3}
list4 = {c1,c1, c2}

大列表包含以下列表: listOfAllColumns = {list1，list2，list3，list4}

And the big list contains these lists: listOfAllColumns = {list1, list2, list3, list4}

现在，我需要一种从listOfAllColumns列表中删除重复列表的方法.例如，它将查看上面的列表并删除list4.

Now I want a method that removes duplicate lists from the listOfAllColumns list. For example, it will look into the list above and remove list4.

list1: c1,c1,c2
list2: c1,c2,c1
list3: c2,c3
list4: c1,c1,c2 (it is equal to list1 so it is a duplicate)

这是我的代码:

public class ColumnList
{
    public void RemoveDuplicateColumnTypes()
    {

        Column c1 = new Column() { SectionName = "C50", StirrupType = "Tie" };
        Column c2 = new Column() { SectionName = "C50", StirrupType = "Spiral" };
        Column c3 = new Column() { SectionName = "C40", StirrupType = "Tie" };


        List<Column> list1 = new List<Column>() { c1, c1, c2 };
        List<Column> list2 = new List<Column>() { c1, c2, c1 };
        List<Column> list3 = new List<Column>() { c2, c3 };
        List<Column> list4 = new List<Column>() { c1, c1, c2 };


        List<List<Column>> listOfAllColumns = new List<List<Column>>() { list1, list2, list3, list4 };

        var result = listOfAllColumns.Distinct();

    }
}

class Column
{
    public string SectionName;
    public string StirrupType;
    public int StirrupSize;
    public double StirrupSpacing;
}

顺便说一句，顺序很重要，例如{c1，c2，c1}与{c2，c1，c1}不同.

By the way the order is important, so for example {c1, c2, c1} is different than {c2,c1,c1}.

推荐答案

我将实现一个自定义的IEqualityComparer<IEnumerable<Column>>，您可以将其用于Distinct:

I would implement a custom IEqualityComparer<IEnumerable<Column>> which you can use for Distinct:

public class ColumnListComparer : IEqualityComparer<IEnumerable<Column>>
{
    public bool Equals(IEnumerable<Column> x, IEnumerable<Column> y)
    {
        if (x == null || y == null) return false;
        if (object.ReferenceEquals(x, y)) return true;
        return x.SequenceEqual(y);
    }

    public int GetHashCode(IEnumerable<Column> obj)
    {
        unchecked
        {
            int hash = 17;
            foreach(Column col in obj)
            {
                hash = hash * 23 + (col == null ? 0 : col.GetHashCode());
            }
            return hash;
        }
    }
}

现在可行:

var result = listOfAllColumns.Distinct(new ColumnListComparer());

您还需要在类Column中覆盖Equals + GetHashCode:

You also need to override Equals + GetHashCode in your class Column:

public class Column
{
    public string SectionName;
    public string StirrupType;
    public int StirrupSize;
    public double StirrupSpacing;

    public override bool Equals(object obj)
    {
        Column col2 = obj as Column;
        if(col2 == null) return false;
        return SectionName    == col2.SectionName
            && StirrupType    == col2.StirrupType 
            && StirrupSize    == col2.StirrupSize
            && StirrupSpacing == col2.StirrupSpacing;
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hash = 17;
            hash = hash * 23 + (SectionName ?? "").GetHashCode();
            hash = hash * 23 + (StirrupType ?? "").GetHashCode();
            hash = hash * 23 + StirrupSize.GetHashCode();
            hash = hash * 23 + StirrupSpacing.GetHashCode();
            return hash;
        }
    }
}

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