Question

我试图解决我需要管理数字范围数组的问题，我需要确保集合中没有数字范围相互冲突。对于那些已经弄明白的人：是的，我在谈论网络，但我正试图简化这篇文章。： - ）

我花了一分钟（或两个人），但我想出了以下逻辑测试：

确定现有的结尾（last）是否小于新的开头（new first）。
确定现有的开头（第一个）是否大于新的结尾（新的最后一个）。
如果＃1的结果与＃2的结果不同，则范围不会发生冲突。

尽我所知（并在Excel中复制），这是合理的逻辑。但是，当我尝试在C＃中的LINQ中编写此逻辑并随后在PowerShell中执行时，它不起作用。我提前为长篇PowerShell输出道歉。

我应该如何在LINQ中编写这个逻辑？我哪里出错了？

C＃代码：

public class NumberRange
{
    public int First;
    public int Last;

    public NumberRange()
    {
    }

    public NumberRange(int first, int last)
    {
        First = first;
        Last = last;
    }
}

public class NumberRangeCollection : Collection<NumberRange>
{
    protected override void InsertItem(int index, NumberRange item)
    {
        NumberRange[] existingItem = this.Where(x => ((x.Last < item.First) != (x.First > item.Last))).ToArray();
        if (existingItem.Any()) throw new ArgumentException("New range collides with an existing range.", "item");

        base.InsertItem(index, item);
    }
}

PowerShell命令：

PS> $range1 = New-Object TestLibrary.NumberRange -ArgumentList @(3, 4)
PS> $range2 = New-Object TestLibrary.NumberRange -ArgumentList @(4, 5)
PS> $range3 = New-Object TestLibrary.NumberRange -ArgumentList @(5, 6)
PS> $bigrange = New-Object TestLibrary.NumberRange -ArgumentList @(3, 6)
PS> $b = New-Object TestLibrary.NumberRangeCollection
PS> $b.Add($range1)
PS> $b.Add($bigrange) # This should fail, but doesn't
PS> $b | Format-Table -AutoSize

First Last
----- ----
    3    4
    3    6


PS> $b = New-Object TestLibrary.NumberRangeCollection
PS> $b.Add($range2)
PS> $b.Add($bigrange) # This should fail, but doesn't
PS> $b | Format-Table -AutoSize

First Last
----- ----
    4    5
    3    6


PS> $b = New-Object TestLibrary.NumberRangeCollection
PS> $b.Add($range3)
PS> $b.Add($bigrange) # This should fail, but doesn't
PS> $b | Format-Table -AutoSize

First Last
----- ----
    5    6
    3    6


PS> $b = New-Object TestLibrary.NumberRangeCollection
PS> $b.Add($range4)
PS> $b.Add($bigrange) # This should fail, does, but doesn't throw the right exception.
Exception calling "Add" with "1" argument(s): "Object reference not set to an instance of an object."
At line:1 char:1
+ $b.Add($bigrange)
+ ~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : NullReferenceException

PS> $b | Format-Table -AutoSize
PS> $b = New-Object TestLibrary.NumberRangeCollection
PS> $b.Add($bigrange)
PS> $b.Add($range1) # This should fail, but doesn't
PS> $b.Add($range2) # This should fail, but doesn't
PS> $b.Add($range3) # WOOT!  The only one that works!
Exception calling "Add" with "1" argument(s): "New range collides with an existing range.
Parameter name: item"
At line:1 char:1
+ $b.Add($range3)
+ ~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ArgumentException

PS> $b.Add($range4) # This should fail, does, but doesn't throw the right exception.
Exception calling "Add" with "1" argument(s): "Object reference not set to an instance of an object."
At line:1 char:1
+ $b.Add($range4)
+ ~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : NullReferenceException

PS> $b | Format-Table -AutoSize

First Last
----- ----
    3    6
    3    4
    4    5

Answer 1

谢谢你@JonSkeet，因为你发现第二个问题就是重写它的建议。

所以，我的问题的答案有两个：

LINQ逻辑是声音（使用！=），但InsertItem中的逻辑被颠倒了。我要么需要更改！= = ==或将if (existingItem.Any())更改为if (!existingItem.Any())。我选择了前者。
$ range4不存在（从其他测试中剩余）。叹息

这是完成的工作代码（全部在C＃中）：

public class NumberRange
{
    public int First;
    public int Last;

    public NumberRange()
    {
    }

    public NumberRange(int first, int last)
    {
        First = first;
        Last = last;
    }
}

public class NumberRangeCollection : Collection<NumberRange>
{
    public NumberRange BigRange = new NumberRange(3, 6);
    public NumberRange Range1 = new NumberRange(3, 4);
    public NumberRange Range2 = new NumberRange(4, 5);
    public NumberRange Range3 = new NumberRange(5, 6);

    protected override void InsertItem(int index, NumberRange item)
    {
        NumberRange[] existingItem = this.Where(x => ((x.Last < item.First) == (x.First > item.Last))).ToArray();
        if (existingItem.Any()) throw new ArgumentException("New range collides with an existing range.", "item");

        base.InsertItem(index, item);
    }

    public NumberRangeCollection RunTest1()
    {
        Clear();
        Add(Range1);
        Add(BigRange);
        return this;
    }

    public NumberRangeCollection RunTest2()
    {
        Clear();
        Add(Range2);
        Add(BigRange);
        return this;
    }

    public NumberRangeCollection RunTest3()
    {
        Clear();
        Add(Range3);
        Add(BigRange);
        return this;
    }

    public NumberRangeCollection RunTest4()
    {
        Clear();
        Add(BigRange);
        try
        {
            Add(Range1);
        }
        catch
        {
        }
        try
        {
            Add(Range2);
        }
        catch
        {
        }
        try
        {
            Add(Range3);
        }
        catch
        {
        }
        return this;
    }
}

LINQ不等于不工作？

1 个答案: