C# 中的数组搜索

Question

我正在尝试搜索一个数组以找到另一个较小的数组值。我使用了嵌套循环，找到的值完美显示。但是，我还想打印未找到的值，谁能帮我改进我的代码，以便在循环中打印未找到的值，而不像我在代码中那样使用文字（代码块//改进代码）

希望任何人都可以提供帮助。

( class Program  
{
    static void Main(string[] args)
    {
        int[] intArray = { 5, 12, 0, 67, 75, 3, 27, 1, 98};
        int[] searchValues = { 0, 25, 99, 12, 3 };
        for (int i = 0; i < searchValues.Length; ++i)
        {
            for (int j = 0; j< intArray.Length; ++j)
            { 
                if (searchValues[i]== intArray[j])
                {
                    Console.WriteLine("The Value {0} Has been found in index {1} of intarray ", searchValues[i], j);
                }               
            }
            // improve the code
            if (i == 1 || i == 2)
            {
                Console.WriteLine("The Value {0} was Not found in intarray ", searchValues[i]);
            }
        }
        Console.Read();
    }
})

Answer 1

使另一个临时数组与具有相同值的搜索数组相同，而是与搜索数组匹配，然后与临时数组匹配，然后当您的 if 语句为真并且您显示匹配的值时，使用 int_max 更新您的临时数组的值。毕竟工作显示临时数组的值不等于int_max。现在将显示不匹配的值。这是最简单的一个。

Answer 2

如果您在 foreach 和 IndexOf 函数上交换嵌套循环，您可以使代码更具可读性。代码如下所示：

int[] intArray = { 5, 12, 0, 67, 75, 3, 27, 1, 98 };
int[] searchValues = { 0, 25, 99, 12, 3 };


foreach (var arr in searchValues)
{
     int index = Array.IndexOf(intArray, arr);
     if (index != -1)
           Console.WriteLine("The Value {0} Has been found in index {1} of intarray ", arr, index);
     else
           Console.WriteLine("The Value {0} was Not found in intarray ", arr);
 }

Console.ReadKey();

Answer 3

使用 LINQ 的更短的解决方案：

searchValues.ToList().Where(val => intArray.Contains(val)).ToList().ForEach(val => Console.WriteLine(string.Format("Index of {0}:\t {1}", val, Array.IndexOf(intArray, val))));
searchValues.ToList().Where(val => !intArray.Contains(val)).ToList().ForEach(val => Console.WriteLine(string.Format("Index of {0}:\t {1}", val, "None")));

输出：

int[] intArray = { 5, 12, 0, 67, 75, 3, 27, 1, 98 };
int[] searchValues = { 0, 25, 99, 12, 3 };

0 的索引：2

12 的索引：1

3 的索引：5

25 的索引：无

99 指数：无

或者如果您不介意打印顺序：

searchValues.ToList().Select(val => new KeyValuePair<int, int>(val, Array.IndexOf(intArray, val))).ToList().ForEach(kvp => Console.WriteLine(string.Format("Index of {0}:\t {1}", kvp.Key, (kvp.Value == -1 ? "None" : kvp.Value.ToString()))));

0 的索引：2

25 的索引：无

99 指数：无

12 的索引：1

3 的索引：5

Answer 4

( class Program  
{
    static void Main(string[] args)
    {
        int[] intArray = { 5, 12, 0, 67, 75, 3, 27, 1, 98};
        int[] searchValues = { 0, 25, 99, 12, 3 };

        foreach (int item in searchValues)
           if (Array.IndexOf(intArray, item)!= -1)
               Console.Writeline("Item exists in list: ",item)
           else Console.Writeline("Item does not exist in list: ",item)

        Console.Read();
    }
})

Answer 5

最简单的方法是将索引存储在一个变量中，然后在内部for循环结束后检查它的值：

for (int i = 0; i < searchValues.Length; ++i)
{
    int idx = -1;

    for (int j = 0; j< intArray.Length; ++j)
    { 
        if (searchValues[i] == intArray[j])
        {
            idx = j;
            break;
        }               
    }
    // improve the code
    if (idx >= 0)
    {
        Console.WriteLine("The Value {0} Has been found in index {1} of intarray ", searchValues[i], idx);
    }
    else
    {
        Console.WriteLine("The Value {0} was Not found in intarray ", searchValues[i]);
    }
}

另一种方法是使用 LINQ：

int[] intArray = { 5, 12, 0, 67, 75, 3, 27, 1, 98};
int[] searchValues = { 0, 25, 99, 12, 3 };

var indices = searchValues.Select(i => new { Value = i, Index = Array.IndexOf(intArray, i) });
var foundValues = indices.Where(x => x.Index >= 0).ToArray();
var unfoundValues = indices.Where(x => x.Index < 0).ToArray();

foreach (var val in foundValues)
    Console.WriteLine("The Value {0} Has been found in index {1} of intarray ", val.Value, val.Index);

foreach (var val in unfoundValues)
    Console.WriteLine("The Value {0} was Not found in intarray ", val.Value);