Array.IndexOf Method
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Searches for the specified object and returns the index of its first occurrence in a one-dimensional array or in a range of elements in the array.
IndexOf(Array, Object) |
Searches for the specified object and returns the index of its first occurrence in a one-dimensional array. |
IndexOf(Array, Object, Int32) |
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of its first occurrence. The range extends from a specified index to the end of the array. |
IndexOf(Array, Object, Int32, Int32) |
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of ifs first occurrence. The range extends from a specified index for a specified number of elements. |
IndexOf<T>(T[], T, Int32) |
Searches for the specified object in a range of elements of a one dimensional array, and returns the index of its first occurrence. The range extends from a specified index to the end of the array. |
IndexOf<T>(T[], T, Int32, Int32) |
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of its first occurrence. The range extends from a specified index for a specified number of elements. |
IndexOf<T>(T[], T) |
Searches for the specified object and returns the index of its first occurrence in a one-dimensional array. |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object and returns the index of its first occurrence in a one-dimensional array.
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
Parameters
- array
- Array
The one-dimensional array to search.
- value
- Object
The object to locate in array
.
Returns
The index of the first occurrence of value
in array
, if found; otherwise, the lower bound of the array minus 1.
Exceptions
array
is null
.
array
is multidimensional.
Examples
The example calls the following three overloads of the IndexOf method to find the index of a string in a string array:
IndexOf(Array, Object), to determine the first occurrence of the string "the" in a string array.
IndexOf(Array, Object, Int32), to determine the first occurrence of the string "the" in the fourth to the last elements of a string array.
IndexOf(Array, Object, Int32, Int32), to determine the first occurrence of the string "the" in a string array from the element that follows the last successful match to the end of the array.
using namespace System;
void main()
{
// Create a string array with 3 elements having the same value.
array<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.
// 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.
Remarks
This method searches all the elements of a one-dimensional array for value
. To determine whether value
exists in array
, the method performs an equality comparison by calling each element's Equals
method until it finds a match. This means that if the element overrides the Object.Equals(Object) method, that override is called.
Because most arrays have a lower bound of zero, this method generally returns -1 ifvalue
isn't found. In the rare case that the lower bound of the array is equal to Int32.MinValue(0x80000000) and value
isn't found, this method returns Int32.MaxValue (0x7FFFFFFF).
This method is an O(n
) operation, where n
is the Length of array
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of its first occurrence. The range extends from a specified index to the end of the array.
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
Parameters
- array
- Array
The one-dimensional array to search.
- value
- Object
The object to locate in array
.
- startIndex
- Int32
The starting index of the search. 0 (zero) is valid in an empty array.
Returns
The index of the first occurrence of value
, if it's found, within the range of elements in array
that extends from startIndex
to the last element; otherwise, the lower bound of the array minus 1.
Exceptions
array
is null
.
startIndex
is outside the range of valid indexes for array
.
array
is multidimensional.
Examples
The example calls the following three overloads of the IndexOf method to find the index of a string in a string array:
IndexOf(Array, Object), to determine the first occurrence of the string "the" in a string array.
IndexOf(Array, Object, Int32), to determine the first occurrence of the string "the" in the fourth to the last elements of a string array.
IndexOf(Array, Object, Int32, Int32), to determine the first occurrence of the string "the" in a string array from the element that follows the last successful match to the end of the array.
using namespace System;
void main()
{
// Create a string array with 3 elements having the same value.
array<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.
// 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.
Remarks
This method searches a one-dimensional array from the element at index startIndex
to the last element. To determine whether value
exists in array
, the method performs an equality comparison by calling the Equals
method of every element until it finds a match. This means that if the element overrides the Object.Equals(Object) method, that override is called.
Because most arrays have a lower bound of zero, this method generally returns -1 if value
isn't found. In the rare case that the lower bound of the array is equal to Int32.MinValue(0x80000000) and value
isn't found, this method returns Int32.MaxValue (0x7FFFFFFF).
If startIndex
equals Array.Length,the method returns -1. If startIndex
is greater than Array.Length, the method throws an ArgumentOutOfRangeException.
This method is an O(n
) operation, where n
is the number of elements from startIndex
to the end of array
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of ifs first occurrence. The range extends from a specified index for a specified number of elements.
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
Parameters
- array
- Array
The one-dimensional array to search.
- value
- Object
The object to locate in array
.
- startIndex
- Int32
The starting index of the search. 0 (zero) is valid in an empty array.
- count
- Int32
The number of elements to search.
Returns
The index of the first occurrence of value
, if it's found in the array
from index startIndex
to startIndex
+ count
- 1; otherwise, the lower bound of the array minus 1.
Exceptions
array
is null
.
startIndex
is outside the range of valid indexes for array
.
-or-
count
is less than zero.
-or-
startIndex
and count
do not specify a valid section in array
.
array
is multidimensional.
Examples
The example calls the following three overloads of the IndexOf method to find the index of a string in a string array:
IndexOf(Array, Object), to determine the first occurrence of the string "the" in a string array.
IndexOf(Array, Object, Int32), to determine the first occurrence of the string "the" in the fourth to the last elements of a string array.
IndexOf(Array, Object, Int32, Int32), to determine the first occurrence of the string "the" in a string array from the element that follows the last successful match to the end of the array. To determine the value of the
count
argument, it subtracts the upper bound of the array from the starting index and adds one.
using namespace System;
void main()
{
// Create a string array with 3 elements having the same value.
array<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.
// 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.
Remarks
This method searches the elements of a one-dimensional array from startIndex
to startIndex
plus count
minus 1, if count
is greater than 0. To determine whether value
exists in array
, the method performs an equality comparison by calling the Equals
method of every element until it finds a match. This means that if the element overrides the Object.Equals method, that override is called.
Because most arrays have a lower bound of zero, this method generally returns -1 when value
isn't found. In the rare case that the lower bound of the array is equal to Int32.MinValue (0x80000000) and value
isn't found, this method returns Int32.MaxValue (0x7FFFFFFF).
If startindex
equals Array.Length, the method returns -1. If startIndex
is greater than Array.Length, the method throws an ArgumentOutOfRangeException.
This method is an O(n
) operation, where n
is count
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object in a range of elements of a one dimensional array, and returns the index of its first occurrence. The range extends from a specified index to the end of the array.
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
Type Parameters
- T
The type of the elements of the array.
Parameters
- array
- T[]
The one-dimensional, zero-based array to search.
- value
- T
The object to locate in array
.
- startIndex
- Int32
The zero-based starting index of the search. 0 (zero) is valid in an empty array.
Returns
The zero-based index of the first occurrence of value
within the range of elements in array
that extends from startIndex
to the last element, if found; otherwise, -1.
Exceptions
array
is null
.
startIndex
is outside the range of valid indexes for array
.
Examples
The following example demonstrates all three generic overloads of the IndexOf method. An array of strings is created, with one entry that appears twice, at index location 0 and index location 5. The IndexOf<T>(T[], T) method overload searches the array from the beginning, and finds the first occurrence of the string. The IndexOf<T>(T[], T, Int32) method overload is used to search the array beginning with index location 3 and continuing to the end of the array, and finds the second occurrence of the string. Finally, the IndexOf<T>(T[], T, Int32, Int32) method overload is used to search a range of two entries, beginning at index location two; it returns -1 because there are no instances of the search string in that range.
using namespace System;
void main()
{
array<String^>^ dinosaurs = { "Tyrannosaurus",
"Amargasaurus",
"Mamenchisaurus",
"Brachiosaurus",
"Deinonychus",
"Tyrannosaurus",
"Compsognathus" };
Console::WriteLine();
for each(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
*/
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
Remarks
This method searches a one-dimensional array from the element at startIndex
to the end of the array. To determine whether value
exists in array
, the method performs an equality comparison by calling the T.Equals
method on every element. This means that if T
overrides the Equals method, that override is called.
If startIndex
equals Length,the method returns -1. If startIndex
is greater than Array.Length, the method throws an ArgumentOutOfRangeException.
This method is an O(n
) operation, where n
is the number of elements from startIndex
to the end of array
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object in a range of elements of a one-dimensional array, and returns the index of its first occurrence. The range extends from a specified index for a specified number of elements.
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
Type Parameters
- T
The type of the elements of the array.
Parameters
- array
- T[]
The one-dimensional, zero-based array to search.
- value
- T
The object to locate in array
.
- startIndex
- Int32
The zero-based starting index of the search. 0 (zero) is valid in an empty array.
- count
- Int32
The number of elements in the section to search.
Returns
The zero-based index of the first occurrence of value
within the range of elements in array
that starts at startIndex
and contains the number of elements specified in count
, if found; otherwise, -1.
Exceptions
array
is null
.
startIndex
is outside the range of valid indexes for array
.
-or-
count
is less than zero.
-or-
startIndex
and count
do not specify a valid section in array
.
Examples
The following example demonstrates all three generic overloads of the IndexOf method. An array of strings is created, with one entry that appears twice, at index location 0 and index location 5. The IndexOf<T>(T[], T) method overload searches the array from the beginning, and finds the first occurrence of the string. The IndexOf<T>(T[], T, Int32) method overload is used to search the array beginning with index location 3 and continuing to the end of the array, and finds the second occurrence of the string. Finally, the IndexOf<T>(T[], T, Int32, Int32) method overload is used to search a range of two entries, beginning at index location two; it returns -1 because there are no instances of the search string in that range.
using namespace System;
void main()
{
array<String^>^ dinosaurs = { "Tyrannosaurus",
"Amargasaurus",
"Mamenchisaurus",
"Brachiosaurus",
"Deinonychus",
"Tyrannosaurus",
"Compsognathus" };
Console::WriteLine();
for each(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
*/
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
Remarks
This method searches the elements of a one-dimensional array from startIndex
to startIndex
plus count
minus 1, if count
is greater than 0. To determine whether value
exists in array
, the method performs an equality comparison by calling the T.Equals
method on every element. This means that if T
overrides the Equals method, that override is called.
If startIndex
equals Array.Length, the method returns -1. If startIndex
is greater than Array.Length, the method throws an ArgumentOutOfRangeException.
This method is an O(n
) operation, where n
is count
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
- Source:
- Array.cs
- Source:
- Array.cs
- Source:
- Array.cs
Searches for the specified object and returns the index of its first occurrence in a one-dimensional array.
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
Type Parameters
- T
The type of the elements of the array.
Parameters
- array
- T[]
The one-dimensional, zero-based array to search.
- value
- T
The object to locate in array
.
Returns
The zero-based index of the first occurrence of value
in the entire array
, if found; otherwise, -1.
Exceptions
array
is null
.
Examples
The following example demonstrates all three generic overloads of the IndexOf method. An array of strings is created, with one entry that appears twice, at index location 0 and index location 5. The IndexOf<T>(T[], T) method overload searches the array from the beginning, and finds the first occurrence of the string. The IndexOf<T>(T[], T, Int32) method overload is used to search the array beginning with index location 3 and continuing to the end of the array, and finds the second occurrence of the string. Finally, the IndexOf<T>(T[], T, Int32, Int32) method overload is used to search a range of two entries, beginning at index location two; it returns -1 because there are no instances of the search string in that range.
using namespace System;
void main()
{
array<String^>^ dinosaurs = { "Tyrannosaurus",
"Amargasaurus",
"Mamenchisaurus",
"Brachiosaurus",
"Deinonychus",
"Tyrannosaurus",
"Compsognathus" };
Console::WriteLine();
for each(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
*/
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
Remarks
This method searches all the elements of a one-dimensional array for value
. To determine whether value
exists in array
, the method performs an equality comparison by calling the T.Equals
method on every element. This means that if T
overrides the Equals method, that override is called.
This method is an O(n
) operation, where n
is the Length of array
.
See also
Applies to
.NET 9 and other versions
Product | Versions |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
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