Array.IndexOf 方法

定义

命名空间:: System

程序集:: mscorlib.dll, System.Runtime.dll

程序集:: netstandard.dll, System.Runtime.dll

程序集:: System.Runtime.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

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搜索指定的对象，并返回其第一个匹配项在一维数组或数组中的一系列元素中的索引。

重载

名称	说明
IndexOf(Array, Object)	搜索指定的对象，并返回其第一个出现在一维数组中的索引。
IndexOf(Array, Object, Int32)	在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定的索引扩展到数组的末尾。
IndexOf(Array, Object, Int32, Int32)	在一维数组的一系列元素中搜索指定的对象，并返回 ifs 首次出现的索引。范围从指定数量的元素的指定索引扩展。
IndexOf<T>(T[], T, Int32)	在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定的索引扩展到数组的末尾。
IndexOf<T>(T[], T, Int32, Int32)	在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定数量的元素的指定索引扩展。
IndexOf<T>(T[], T)	搜索指定的对象，并返回其第一个出现在一维数组中的索引。

IndexOf(Array, Object)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

搜索指定的对象，并返回其第一个出现在一维数组中的索引。

public:
 static int IndexOf(Array ^ array, System::Object ^ value);

public static int IndexOf(Array array, object value);

public static int IndexOf(Array array, object? value);

static member IndexOf : Array * obj -> int

Public Shared Function IndexOf (array As Array, value As Object) As Integer

参数

array: Array

要搜索的一维数组。

value: Object

要查找到 array的对象的对象。

Int32

如果找到，则为第一个 value 匹配项 array的索引;否则，数组的下限减 1。

例外

ArgumentNullException

array 是 null。

RankException

array 是多维。

示例

该示例调用方法的以下三个重载 IndexOf 来查找字符串数组中的字符串索引：

IndexOf(Array, Object)，用于确定字符串数组中字符串“the”的第一个匹配项。
IndexOf(Array, Object, Int32)，确定字符串“the”在第四个到字符串数组的最后一个元素中的第一个匹配项。
IndexOf(Array, Object, Int32, Int32)，用于确定字符串数组中字符串“the”的第一个匹配项，该字符串位于最后一次成功匹配到数组末尾之后的元素中。

// Create a string array with 3 elements having the same value.
let strings = 
    [| "the"; "quick"; "brown"; "fox"; "jumps"; "over"
       "the"; "lazy"; "dog"; "in"; "the"; "barn" |]

// Display the elements of the array.
printfn "The array contains the following values:"
for i = strings.GetLowerBound 0 to strings.GetUpperBound 0 do
    printfn $"   [{i,2}]: {strings[i]}"

// Search for the first occurrence of the duplicated value.
let searchString = "the"
let index = Array.IndexOf(strings, searchString)
printfn $"The first occurrence of \"{searchString}\" is at index {index}."

// Search for the first occurrence of the duplicated value in the last section of the array.
let index = Array.IndexOf(strings, searchString, 4)
printfn $"The first occurrence of \"{searchString}\" between index 4 and the end is at index {index}."

// Search for the first occurrence of the duplicated value in a section of the array.
let position = index + 1
let index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound 0 - position + 1)
printfn $"The first occurrence of \"{searchString}\" between index {position} and index {strings.GetUpperBound 0} is at index {index}."

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

// Create a string array with 3 elements having the same value.
String[] strings = { "the", "quick", "brown", "fox", "jumps",
                     "over", "the", "lazy", "dog", "in", "the",
                     "barn" };

// Display the elements of the array.
Console.WriteLine("The array contains the following values:");
for (int i = strings.GetLowerBound(0); i <= strings.GetUpperBound(0); i++)
   Console.WriteLine("   [{0,2}]: {1}", i, strings[i]);

// Search for the first occurrence of the duplicated value.
string searchString = "the";
int index = Array.IndexOf(strings, searchString);
Console.WriteLine("The first occurrence of \"{0}\" is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in the last section of the array.
index = Array.IndexOf(strings, searchString, 4);
Console.WriteLine("The first occurrence of \"{0}\" between index 4 and the end is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in a section of the array.
int position = index + 1;
index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1);
Console.WriteLine("The first occurrence of \"{0}\" between index {1} and index {2} is at index {3}.",
                  searchString, position, strings.GetUpperBound(0), index);

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

Public Module Example
   Public Sub Main()
      ' Create a string array with 3 elements having the same value.
      Dim strings() As String = { "the", "quick", "brown", "fox",
                                  "jumps", "over", "the", "lazy",
                                  "dog", "in", "the", "barn" }

      ' Display the values of the array.
      Console.WriteLine("The array contains the following values:")
      For i As Integer = strings.GetLowerBound(0) To strings.GetUpperBound(0)
         Console.WriteLine("   [{0,2}]: {1}", i, strings(i))
      Next

      ' Search for the first occurrence of the duplicated value.
      Dim searchString As String = "the"
      Dim index As Integer = Array.IndexOf(strings, searchString)
      Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in the last section of the array.
      index = Array.IndexOf(strings, searchString, 4)
      Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in a section of the array.
       Dim position As Integer = index + 1
       index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1)
       Console.WriteLine("The first occurrence of ""{0}"" between index {1} and index {2} is at index {3}.",
                         searchString, position, strings.GetUpperBound(0), index)
    End Sub
End Module
' The example displays the following output:
'    The array contains the following values:
'       [ 0]: the
'       [ 1]: quick
'       [ 2]: brown
'       [ 3]: fox
'       [ 4]: jumps
'       [ 5]: over
'       [ 6]: the
'       [ 7]: lazy
'       [ 8]: dog
'       [ 9]: in
'       [10]: the
'       [11]: barn
'    The first occurrence of "the" is at index 0.
'    The first occurrence of "the" between index 4 and the end is at index 6.
'    The first occurrence of "the" between index 7 and index 11 is at index 10.

注解

此方法搜索一维数组 value的所有元素。若要确定 value 是否存在于 array其中，该方法使用默认相等比较器 EqualityComparer<T>.Default执行相等比较。

由于大多数数组的下限为零，因此此方法通常返回 -1（如果未value 找到）。在极少数情况下，数组的下限等于 Int32.MinValue（0x80000000）， value 并且找不到，此方法返回 Int32.MaxValue （0x7FFFFFFF）。

此方法是 O（n）操作，其位置 n 为 Lengtharray.

另请参阅

LastIndexOf

适用于

IndexOf(Array, Object, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定的索引扩展到数组的末尾。

public:
 static int IndexOf(Array ^ array, System::Object ^ value, int startIndex);

public static int IndexOf(Array array, object value, int startIndex);

public static int IndexOf(Array array, object? value, int startIndex);

static member IndexOf : Array * obj * int -> int

Public Shared Function IndexOf (array As Array, value As Object, startIndex As Integer) As Integer

参数

array: Array

要搜索的一维数组。

value: Object

要查找到 array的对象的对象。

startIndex: Int32

搜索的起始索引。 0 （零）在空数组中有效。

Int32

如果找到第一个 value匹配项的索引，则在其元素 array 范围内从 startIndex 最后一个元素扩展到最后一个元素;否则，数组的下限减 1。

例外

ArgumentNullException

array 是 null。

ArgumentOutOfRangeException

startIndex 超出了有效索引 array的范围。

RankException

array 是多维。

示例

该示例调用方法的以下三个重载 IndexOf 来查找字符串数组中的字符串索引：

IndexOf(Array, Object)，用于确定字符串数组中字符串“the”的第一个匹配项。
IndexOf(Array, Object, Int32)，确定字符串“the”在第四个到字符串数组的最后一个元素中的第一个匹配项。
IndexOf(Array, Object, Int32, Int32)，用于确定字符串数组中字符串“the”的第一个匹配项，该字符串位于最后一次成功匹配到数组末尾之后的元素中。

// Create a string array with 3 elements having the same value.
let strings = 
    [| "the"; "quick"; "brown"; "fox"; "jumps"; "over"
       "the"; "lazy"; "dog"; "in"; "the"; "barn" |]

// Display the elements of the array.
printfn "The array contains the following values:"
for i = strings.GetLowerBound 0 to strings.GetUpperBound 0 do
    printfn $"   [{i,2}]: {strings[i]}"

// Search for the first occurrence of the duplicated value.
let searchString = "the"
let index = Array.IndexOf(strings, searchString)
printfn $"The first occurrence of \"{searchString}\" is at index {index}."

// Search for the first occurrence of the duplicated value in the last section of the array.
let index = Array.IndexOf(strings, searchString, 4)
printfn $"The first occurrence of \"{searchString}\" between index 4 and the end is at index {index}."

// Search for the first occurrence of the duplicated value in a section of the array.
let position = index + 1
let index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound 0 - position + 1)
printfn $"The first occurrence of \"{searchString}\" between index {position} and index {strings.GetUpperBound 0} is at index {index}."

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

// Create a string array with 3 elements having the same value.
String[] strings = { "the", "quick", "brown", "fox", "jumps",
                     "over", "the", "lazy", "dog", "in", "the",
                     "barn" };

// Display the elements of the array.
Console.WriteLine("The array contains the following values:");
for (int i = strings.GetLowerBound(0); i <= strings.GetUpperBound(0); i++)
   Console.WriteLine("   [{0,2}]: {1}", i, strings[i]);

// Search for the first occurrence of the duplicated value.
string searchString = "the";
int index = Array.IndexOf(strings, searchString);
Console.WriteLine("The first occurrence of \"{0}\" is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in the last section of the array.
index = Array.IndexOf(strings, searchString, 4);
Console.WriteLine("The first occurrence of \"{0}\" between index 4 and the end is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in a section of the array.
int position = index + 1;
index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1);
Console.WriteLine("The first occurrence of \"{0}\" between index {1} and index {2} is at index {3}.",
                  searchString, position, strings.GetUpperBound(0), index);

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

Public Module Example
   Public Sub Main()
      ' Create a string array with 3 elements having the same value.
      Dim strings() As String = { "the", "quick", "brown", "fox",
                                  "jumps", "over", "the", "lazy",
                                  "dog", "in", "the", "barn" }

      ' Display the values of the array.
      Console.WriteLine("The array contains the following values:")
      For i As Integer = strings.GetLowerBound(0) To strings.GetUpperBound(0)
         Console.WriteLine("   [{0,2}]: {1}", i, strings(i))
      Next

      ' Search for the first occurrence of the duplicated value.
      Dim searchString As String = "the"
      Dim index As Integer = Array.IndexOf(strings, searchString)
      Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in the last section of the array.
      index = Array.IndexOf(strings, searchString, 4)
      Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in a section of the array.
       Dim position As Integer = index + 1
       index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1)
       Console.WriteLine("The first occurrence of ""{0}"" between index {1} and index {2} is at index {3}.",
                         searchString, position, strings.GetUpperBound(0), index)
    End Sub
End Module
' The example displays the following output:
'    The array contains the following values:
'       [ 0]: the
'       [ 1]: quick
'       [ 2]: brown
'       [ 3]: fox
'       [ 4]: jumps
'       [ 5]: over
'       [ 6]: the
'       [ 7]: lazy
'       [ 8]: dog
'       [ 9]: in
'       [10]: the
'       [11]: barn
'    The first occurrence of "the" is at index 0.
'    The first occurrence of "the" between index 4 and the end is at index 6.
'    The first occurrence of "the" between index 7 and index 11 is at index 10.

注解

此方法从索引 startIndex 处的元素到最后一个元素搜索一维数组。若要确定 value 是否存在于 array其中，该方法使用默认相等比较器 EqualityComparer<T>.Default执行相等比较。

由于大多数数组的下限为零，因此此方法通常返回 -1（如果未 value 找到）。在极少数情况下，数组的下限等于 Int32.MinValue（0x80000000）， value 并且找不到，此方法返回 Int32.MaxValue （0x7FFFFFFF）。

如果 startIndex 等于 Array.Length，则该方法返回 -1。如果 startIndex 大于 Array.Length，该方法将引发一个 ArgumentOutOfRangeException。

此方法是一个 O（n）操作，其中 n 元素数从 startIndex 到尾 array。

另请参阅

适用于

IndexOf(Array, Object, Int32, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

在一维数组的一系列元素中搜索指定的对象，并返回 ifs 首次出现的索引。范围从指定数量的元素的指定索引扩展。

public:
 static int IndexOf(Array ^ array, System::Object ^ value, int startIndex, int count);

public static int IndexOf(Array array, object value, int startIndex, int count);

public static int IndexOf(Array array, object? value, int startIndex, int count);

static member IndexOf : Array * obj * int * int -> int

Public Shared Function IndexOf (array As Array, value As Object, startIndex As Integer, count As Integer) As Integer

参数

array: Array

要搜索的一维数组。

value: Object

要查找到 array的对象的对象。

startIndex: Int32

搜索的起始索引。 0 （零）在空数组中有效。

count: Int32

要搜索的元素数。

Int32

如果在从索引到 + countstartIndex-1 中找到array第一个匹配项value的索引startIndex;否则，数组的下限减 1。

例外

ArgumentNullException

array 是 null。

ArgumentOutOfRangeException

startIndex 超出了有效索引 array的范围。

-或-

count 小于零。

-或-

startIndex 且 count 未在 . 中 array指定有效节。

RankException

array 是多维。

示例

该示例调用方法的以下三个重载 IndexOf 来查找字符串数组中的字符串索引：

IndexOf(Array, Object)，用于确定字符串数组中字符串“the”的第一个匹配项。
IndexOf(Array, Object, Int32)，确定字符串“the”在第四个到字符串数组的最后一个元素中的第一个匹配项。
IndexOf(Array, Object, Int32, Int32)，用于确定字符串数组中字符串“the”的第一个匹配项，该字符串位于最后一次成功匹配到数组末尾之后的元素中。若要确定参数的值 count ，它从起始索引中减去数组的上限，并添加一个。

// Create a string array with 3 elements having the same value.
let strings = 
    [| "the"; "quick"; "brown"; "fox"; "jumps"; "over"
       "the"; "lazy"; "dog"; "in"; "the"; "barn" |]

// Display the elements of the array.
printfn "The array contains the following values:"
for i = strings.GetLowerBound 0 to strings.GetUpperBound 0 do
    printfn $"   [{i,2}]: {strings[i]}"

// Search for the first occurrence of the duplicated value.
let searchString = "the"
let index = Array.IndexOf(strings, searchString)
printfn $"The first occurrence of \"{searchString}\" is at index {index}."

// Search for the first occurrence of the duplicated value in the last section of the array.
let index = Array.IndexOf(strings, searchString, 4)
printfn $"The first occurrence of \"{searchString}\" between index 4 and the end is at index {index}."

// Search for the first occurrence of the duplicated value in a section of the array.
let position = index + 1
let index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound 0 - position + 1)
printfn $"The first occurrence of \"{searchString}\" between index {position} and index {strings.GetUpperBound 0} is at index {index}."

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

// Create a string array with 3 elements having the same value.
String[] strings = { "the", "quick", "brown", "fox", "jumps",
                     "over", "the", "lazy", "dog", "in", "the",
                     "barn" };

// Display the elements of the array.
Console.WriteLine("The array contains the following values:");
for (int i = strings.GetLowerBound(0); i <= strings.GetUpperBound(0); i++)
   Console.WriteLine("   [{0,2}]: {1}", i, strings[i]);

// Search for the first occurrence of the duplicated value.
string searchString = "the";
int index = Array.IndexOf(strings, searchString);
Console.WriteLine("The first occurrence of \"{0}\" is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in the last section of the array.
index = Array.IndexOf(strings, searchString, 4);
Console.WriteLine("The first occurrence of \"{0}\" between index 4 and the end is at index {1}.",
                  searchString, index);

// Search for the first occurrence of the duplicated value in a section of the array.
int position = index + 1;
index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1);
Console.WriteLine("The first occurrence of \"{0}\" between index {1} and index {2} is at index {3}.",
                  searchString, position, strings.GetUpperBound(0), index);

// The example displays the following output:
//    The array contains the following values:
//       [ 0]: the
//       [ 1]: quick
//       [ 2]: brown
//       [ 3]: fox
//       [ 4]: jumps
//       [ 5]: over
//       [ 6]: the
//       [ 7]: lazy
//       [ 8]: dog
//       [ 9]: in
//       [10]: the
//       [11]: barn
//    The first occurrence of "the" is at index 0.
//    The first occurrence of "the" between index 4 and the end is at index 6.
//    The first occurrence of "the" between index 7 and index 11 is at index 10.

Public Module Example
   Public Sub Main()
      ' Create a string array with 3 elements having the same value.
      Dim strings() As String = { "the", "quick", "brown", "fox",
                                  "jumps", "over", "the", "lazy",
                                  "dog", "in", "the", "barn" }

      ' Display the values of the array.
      Console.WriteLine("The array contains the following values:")
      For i As Integer = strings.GetLowerBound(0) To strings.GetUpperBound(0)
         Console.WriteLine("   [{0,2}]: {1}", i, strings(i))
      Next

      ' Search for the first occurrence of the duplicated value.
      Dim searchString As String = "the"
      Dim index As Integer = Array.IndexOf(strings, searchString)
      Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in the last section of the array.
      index = Array.IndexOf(strings, searchString, 4)
      Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.",
                        searchString, index)
        
      ' Search for the first occurrence of the duplicated value in a section of the array.
       Dim position As Integer = index + 1
       index = Array.IndexOf(strings, searchString, position, strings.GetUpperBound(0) - position + 1)
       Console.WriteLine("The first occurrence of ""{0}"" between index {1} and index {2} is at index {3}.",
                         searchString, position, strings.GetUpperBound(0), index)
    End Sub
End Module
' The example displays the following output:
'    The array contains the following values:
'       [ 0]: the
'       [ 1]: quick
'       [ 2]: brown
'       [ 3]: fox
'       [ 4]: jumps
'       [ 5]: over
'       [ 6]: the
'       [ 7]: lazy
'       [ 8]: dog
'       [ 9]: in
'       [10]: the
'       [11]: barn
'    The first occurrence of "the" is at index 0.
'    The first occurrence of "the" between index 4 and the end is at index 6.
'    The first occurrence of "the" between index 7 and index 11 is at index 10.

注解

此方法在一维数组的元素中搜索 startIndexstartIndexcount 一维数组的元素（如果 count 大于 0）。若要确定 value 是否存在于 array其中，该方法使用默认相等比较器 EqualityComparer<T>.Default执行相等比较。

由于大多数数组的下限为零，因此此方法通常在找不到时 value 返回 -1。在极少数情况下，数组的下限等于 Int32.MinValue （0x80000000）， value 并且找不到，此方法返回 Int32.MaxValue （0x7FFFFFFF）。

如果 startindex 相等 Array.Length，则该方法返回 -1。如果 startIndex 大于 Array.Length，该方法将引发一个 ArgumentOutOfRangeException。

此方法是 O（n）操作，其中 n 。count

另请参阅

适用于

IndexOf<T>(T[], T, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定的索引扩展到数组的末尾。

public:
generic <typename T>
 static int IndexOf(cli::array <T> ^ array, T value, int startIndex);

public static int IndexOf<T>(T[] array, T value, int startIndex);

static member IndexOf : 'T[] * 'T * int -> int

Public Shared Function IndexOf(Of T) (array As T(), value As T, startIndex As Integer) As Integer

类型参数

T

数组元素的类型。

参数

array: T[]

要搜索的一维从零开始的数组。

value: T

要查找到 array的对象的对象。

startIndex: Int32

从零开始的搜索索引。 0 （零）在空数组中有效。

Int32

如果找到，则从该范围扩展到startIndex最后一个元素的元素array范围内的第一个匹配value项的从零开始的索引;否则为 -1。

例外

ArgumentNullException

array 是 null。

ArgumentOutOfRangeException

startIndex 超出了有效索引 array的范围。

示例

下面的示例演示了该方法的所有三个 IndexOf 泛型重载。创建字符串数组，其中一个条目出现在索引位置 0 和索引位置 5 处两次。方法 IndexOf<T>(T[], T) 重载从头开始搜索数组，并查找字符串的第一个匹配项。方法 IndexOf<T>(T[], T, Int32) 重载用于搜索从索引位置 3 开始的数组，并继续到数组的末尾，并查找字符串的第二个匹配项。最后， IndexOf<T>(T[], T, Int32, Int32) 方法重载用于搜索一系列两个条目，从索引位置 2 开始;它返回 -1，因为该区域中没有搜索字符串的实例。

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
    Console.WriteLine(dinosaur);
}

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus"));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2));

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1
*/

open System

let dinosaurs =
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

printfn ""
for dino in dinosaurs do
    printfn $"{dino}"

Array.IndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): %i"

// This code example produces the following output:
//
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 2, 2): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

注解

此方法在数组末尾的元素中 startIndex 搜索一维数组。若要确定 value 是否存在于 array其中，该方法使用默认相等比较器 EqualityComparer<T>.Default执行相等比较。

如果 startIndex 等于 Length，则该方法返回 -1。如果 startIndex 大于 Array.Length，该方法将引发一个 ArgumentOutOfRangeException。

此方法是一个 O（n）操作，其中 n 元素数从 startIndex 到尾 array。

另请参阅

适用于

IndexOf<T>(T[], T, Int32, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

在一维数组的一系列元素中搜索指定的对象，并返回其第一个匹配项的索引。范围从指定数量的元素的指定索引扩展。

public:
generic <typename T>
 static int IndexOf(cli::array <T> ^ array, T value, int startIndex, int count);

public static int IndexOf<T>(T[] array, T value, int startIndex, int count);

static member IndexOf : 'T[] * 'T * int * int -> int

Public Shared Function IndexOf(Of T) (array As T(), value As T, startIndex As Integer, count As Integer) As Integer

类型参数

T

数组元素的类型。

参数

array: T[]

要搜索的一维从零开始的数组。

value: T

要查找到 array的对象的对象。

startIndex: Int32

从零开始的搜索索引。 0 （零）在空数组中有效。

count: Int32

要搜索的节中的元素数。

Int32

从startIndex零开始的元素array范围内的第一个匹配value项的索引，如果找到，则包含指定元素count的数目;否则为 -1。

例外

ArgumentNullException

array 是 null。

ArgumentOutOfRangeException

startIndex 超出了有效索引 array的范围。

-或-

count 小于零。

-或-

startIndex 且 count 未在 . 中 array指定有效节。

示例

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
    Console.WriteLine(dinosaur);
}

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus"));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2));

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1
*/

open System

let dinosaurs =
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

printfn ""
for dino in dinosaurs do
    printfn $"{dino}"

Array.IndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): %i"

// This code example produces the following output:
//
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 2, 2): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

注解

如果 startIndex 相等 Array.Length，则该方法返回 -1。如果 startIndex 大于 Array.Length，该方法将引发一个 ArgumentOutOfRangeException。

此方法是 O（n）操作，其中 n 。count

另请参阅

适用于

IndexOf<T>(T[], T)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

搜索指定的对象，并返回其第一个出现在一维数组中的索引。

public:
generic <typename T>
 static int IndexOf(cli::array <T> ^ array, T value);

public static int IndexOf<T>(T[] array, T value);

static member IndexOf : 'T[] * 'T -> int

Public Shared Function IndexOf(Of T) (array As T(), value As T) As Integer

类型参数

T

数组元素的类型。

参数

array: T[]

要搜索的一维从零开始的数组。

value: T

要查找到 array的对象的对象。

Int32

如果找到，则为整个array第一个匹配项value的从零开始的索引;否则为 -1。

例外

ArgumentNullException

array 是 null。

示例

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
    Console.WriteLine(dinosaur);
}

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus"));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3));

Console.WriteLine(
    "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): {0}",
    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2));

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1
*/

open System

let dinosaurs =
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

printfn ""
for dino in dinosaurs do
    printfn $"{dino}"

Array.IndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2)
|> printfn "\nArray.IndexOf(dinosaurs, \"Tyrannosaurus\", 2, 2): %i"

// This code example produces the following output:
//
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
//
//    Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.IndexOf(dinosaurs, ""Tyrannosaurus"", 2, 2): {0}", _
            Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus"): 0
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 3): 5
'
'Array.IndexOf(dinosaurs, "Tyrannosaurus", 2, 2): -1

注解

此方法搜索一维数组 value的所有元素。若要确定 value 是否存在于 array其中，该方法使用默认相等比较器 EqualityComparer<T>.Default执行相等比较。

此方法是 O（n）操作，其位置 n 为 Lengtharray.

另请参阅

适用于

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通过

Array.IndexOf 方法

定义

重载

IndexOf(Array, Object)

参数

返回

例外

示例

注解

另请参阅

适用于

IndexOf(Array, Object, Int32)

参数

返回

例外

示例

注解

另请参阅

适用于

IndexOf(Array, Object, Int32, Int32)

参数

返回

例外

示例

注解

另请参阅

适用于

IndexOf<T>(T[], T, Int32)

类型参数

参数

返回

例外

示例

注解

另请参阅

适用于

IndexOf<T>(T[], T, Int32, Int32)

类型参数

参数

返回

例外

示例

注解

另请参阅

适用于

IndexOf<T>(T[], T)

类型参数

参数

返回

例外

示例

注解

另请参阅

适用于

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