使用字符串实现自定义IComparer
本文关键字:自定义 IComparer 实现 字符串 | 更新日期: 2023-09-27 18:21:06
例如,我在c#中有一个字符串集合;
var example = new string[]{"c", "b", "a", "d"};
然后我用对它进行排序,但我的IComparer方法不起作用,并且根据事物的外观无限循环。
基本上,我需要"b"
先来,然后是"c"
,然后我不在乎其他人的顺序。
这可能使用I Comparer<string>
和Compare(string x, string y)
方法吗?
编辑:编码
public int Compare(string x, string y)
{
var sOrder = new string[] { "b", "c" };
int index_x = -1;
int index_y = -1;
for (int i = 0; i < sOrder.Length;i++)
{
if (sOrder[i] == x)
index_x = i;
else if (sOrder[i] == y)
index_y = i;
}
if (index_x >= 0 && index_y >= 0)
{
if (index_x < index_y)
{
return -1;
}
else
return 1;
}
return 0;
}
这应该可以实现您想要的:
var example = new string[]{"c", "a", "d", "b"};
var comparer = new CustomStringComparer(StringComparer.CurrentCulture);
Array.Sort(example, comparer);
...
class CustomStringComparer : IComparer<string>
{
private readonly IComparer<string> _baseComparer;
public CustomStringComparer(IComparer<string> baseComparer)
{
_baseComparer = baseComparer;
}
public int Compare(string x, string y)
{
if (_baseComparer.Compare(x, y) == 0)
return 0;
// "b" comes before everything else
if (_baseComparer.Compare(x, "b") == 0)
return -1;
if (_baseComparer.Compare(y, "b") == 0)
return 1;
// "c" comes next
if (_baseComparer.Compare(x, "c") == 0)
return -1;
if (_baseComparer.Compare(y, "c") == 0)
return 1;
return _baseComparer.Compare(x, y);
}
}
一个简单的方法是用整数代替字符串。
class MyComparer : IComparer<string>
{
public override int Compare(string x, string y)
{
int ix = x == "b" ? 0 : x == "c" ? 1 : 2;
int iy = y == "b" ? 0 : y == "c" ? 1 : 2;
return ix.CompareTo(iy);
}
}
var example = new List<string> { "c", "b", "a", "d", "foo", "", "1", "e"};
example.Sort(new MyComparer());
foreach (var s in example)
Console.WriteLine(s);
输出:
b
c1
e
a
d
foo
请注意,这不是一个稳定的排序。如果你需要一个稳定排序,需要做更多的工作。