Array Class
Provides methods for creating, manipulating, searching, and sorting arrays, thereby serving as the base class for all arrays in the common language runtime.
Assembly: mscorlib (in mscorlib.dll)
The Array type exposes the following members.
Name | Description | |
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IsFixedSize | Gets a value indicating whether the Array has a fixed size. | |
IsReadOnly | Gets a value indicating whether the Array is read-only. | |
IsSynchronized | Gets a value indicating whether access to the Array is synchronized (thread safe). | |
Length | Gets a 32-bit integer that represents the total number of elements in all the dimensions of the Array. | |
LongLength | Gets a 64-bit integer that represents the total number of elements in all the dimensions of the Array. | |
Rank | Gets the rank (number of dimensions) of the Array. | |
SyncRoot | Gets an object that can be used to synchronize access to the Array. |
Name | Description | |
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AsReadOnly<T> | Returns a read-only wrapper for the specified array. | |
BinarySearch(Array, Object) | Searches an entire one-dimensional sorted Array for a specific element, using the IComparable interface implemented by each element of the Array and by the specified object. | |
BinarySearch(Array, Object, IComparer) | Searches an entire one-dimensional sorted Array for a value using the specified IComparer interface. | |
BinarySearch(Array, Int32, Int32, Object) | Searches a range of elements in a one-dimensional sorted Array for a value, using the IComparable interface implemented by each element of the Array and by the specified value. | |
BinarySearch(Array, Int32, Int32, Object, IComparer) | Searches a range of elements in a one-dimensional sorted Array for a value, using the specified IComparer interface. | |
BinarySearch<T>(T[], T) | Searches an entire one-dimensional sorted Array for a specific element, using the IComparable<T> generic interface implemented by each element of the Array and by the specified object. | |
BinarySearch<T>(T[], T, IComparer<T>) | Searches an entire one-dimensional sorted Array for a value using the specified IComparer<T> generic interface. | |
BinarySearch<T>(T[], Int32, Int32, T) | Searches a range of elements in a one-dimensional sorted Array for a value, using the IComparable<T> generic interface implemented by each element of the Array and by the specified value. | |
BinarySearch<T>(T[], Int32, Int32, T, IComparer<T>) | Searches a range of elements in a one-dimensional sorted Array for a value, using the specified IComparer<T> generic interface. | |
Clear | Sets a range of elements in the Array to zero, to false, or to null, depending on the element type. | |
Clone | Creates a shallow copy of the Array. | |
ConstrainedCopy | Copies a range of elements from an Array starting at the specified source index and pastes them to another Array starting at the specified destination index. Guarantees that all changes are undone if the copy does not succeed completely. | |
ConvertAll<TInput, TOutput> | Converts an array of one type to an array of another type. | |
Copy(Array, Array, Int32) | Copies a range of elements from an Array starting at the first element and pastes them into another Array starting at the first element. The length is specified as a 32-bit integer. | |
Copy(Array, Array, Int64) | Copies a range of elements from an Array starting at the first element and pastes them into another Array starting at the first element. The length is specified as a 64-bit integer. | |
Copy(Array, Int32, Array, Int32, Int32) | Copies a range of elements from an Array starting at the specified source index and pastes them to another Array starting at the specified destination index. The length and the indexes are specified as 32-bit integers. | |
Copy(Array, Int64, Array, Int64, Int64) | Copies a range of elements from an Array starting at the specified source index and pastes them to another Array starting at the specified destination index. The length and the indexes are specified as 64-bit integers. | |
CopyTo(Array, Int32) | Copies all the elements of the current one-dimensional Array to the specified one-dimensional Array starting at the specified destination Array index. The index is specified as a 32-bit integer. | |
CopyTo(Array, Int64) | Copies all the elements of the current one-dimensional Array to the specified one-dimensional Array starting at the specified destination Array index. The index is specified as a 64-bit integer. | |
CreateInstance(Type, Int32) | Creates a one-dimensional Array of the specified Type and length, with zero-based indexing. | |
CreateInstance(Type, Int32[]) | Creates a multidimensional Array of the specified Type and dimension lengths, with zero-based indexing. The dimension lengths are specified in an array of 32-bit integers. | |
CreateInstance(Type, Int64[]) | Creates a multidimensional Array of the specified Type and dimension lengths, with zero-based indexing. The dimension lengths are specified in an array of 64-bit integers. | |
CreateInstance(Type, Int32, Int32) | Creates a two-dimensional Array of the specified Type and dimension lengths, with zero-based indexing. | |
CreateInstance(Type, Int32[], Int32[]) | Creates a multidimensional Array of the specified Type and dimension lengths, with the specified lower bounds. | |
CreateInstance(Type, Int32, Int32, Int32) | Creates a three-dimensional Array of the specified Type and dimension lengths, with zero-based indexing. | |
Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) | |
Exists<T> | Determines whether the specified array contains elements that match the conditions defined by the specified predicate. | |
Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) | |
Find<T> | Searches for an element that matches the conditions defined by the specified predicate, and returns the first occurrence within the entire Array. | |
FindAll<T> | Retrieves all the elements that match the conditions defined by the specified predicate. | |
FindIndex<T>(T[], Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire Array. | |
FindIndex<T>(T[], Int32, Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the Array that extends from the specified index to the last element. | |
FindIndex<T>(T[], Int32, Int32, Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the Array that starts at the specified index and contains the specified number of elements. | |
FindLast<T> | Searches for an element that matches the conditions defined by the specified predicate, and returns the last occurrence within the entire Array. | |
FindLastIndex<T>(T[], Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the entire Array. | |
FindLastIndex<T>(T[], Int32, Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the Array that extends from the first element to the specified index. | |
FindLastIndex<T>(T[], Int32, Int32, Predicate<T>) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the Array that contains the specified number of elements and ends at the specified index. | |
ForEach<T> | Performs the specified action on each element of the specified array. | |
GetEnumerator | Returns an IEnumerator for the Array. | |
GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) | |
GetLength | Gets a 32-bit integer that represents the number of elements in the specified dimension of the Array. | |
GetLongLength | Gets a 64-bit integer that represents the number of elements in the specified dimension of the Array. | |
GetLowerBound | Gets the lower bound of the specified dimension in the Array. | |
GetType | Gets the Type of the current instance. (Inherited from Object.) | |
GetUpperBound | Gets the upper bound of the specified dimension in the Array. | |
GetValue(Int32) | Gets the value at the specified position in the one-dimensional Array. The index is specified as a 32-bit integer. | |
GetValue(Int32[]) | Gets the value at the specified position in the multidimensional Array. The indexes are specified as an array of 32-bit integers. | |
GetValue(Int64) | Gets the value at the specified position in the one-dimensional Array. The index is specified as a 64-bit integer. | |
GetValue(Int64[]) | Gets the value at the specified position in the multidimensional Array. The indexes are specified as an array of 64-bit integers. | |
GetValue(Int32, Int32) | Gets the value at the specified position in the two-dimensional Array. The indexes are specified as 32-bit integers. | |
GetValue(Int64, Int64) | Gets the value at the specified position in the two-dimensional Array. The indexes are specified as 64-bit integers. | |
GetValue(Int32, Int32, Int32) | Gets the value at the specified position in the three-dimensional Array. The indexes are specified as 32-bit integers. | |
GetValue(Int64, Int64, Int64) | Gets the value at the specified position in the three-dimensional Array. The indexes are specified as 64-bit integers. | |
IndexOf(Array, Object) | Searches for the specified object and returns the index of the first occurrence within the entire one-dimensional Array. | |
IndexOf(Array, Object, Int32) | Searches for the specified object and returns the index of the first occurrence within the range of elements in the one-dimensional Array that extends from the specified index to the last element. | |
IndexOf(Array, Object, Int32, Int32) | Searches for the specified object and returns the index of the first occurrence within the range of elements in the one-dimensional Array that starts at the specified index and contains the specified number of elements. | |
IndexOf<T>(T[], T) | Searches for the specified object and returns the index of the first occurrence within the entire Array. | |
IndexOf<T>(T[], T, Int32) | Searches for the specified object and returns the index of the first occurrence within the range of elements in the Array that extends from the specified index to the last element. | |
IndexOf<T>(T[], T, Int32, Int32) | Searches for the specified object and returns the index of the first occurrence within the range of elements in the Array that starts at the specified index and contains the specified number of elements. | |
Initialize | Initializes every element of the value-type Array by calling the default constructor of the value type. | |
LastIndexOf(Array, Object) | Searches for the specified object and returns the index of the last occurrence within the entire one-dimensional Array. | |
LastIndexOf(Array, Object, Int32) | Searches for the specified object and returns the index of the last occurrence within the range of elements in the one-dimensional Array that extends from the first element to the specified index. | |
LastIndexOf(Array, Object, Int32, Int32) | Searches for the specified object and returns the index of the last occurrence within the range of elements in the one-dimensional Array that contains the specified number of elements and ends at the specified index. | |
LastIndexOf<T>(T[], T) | Searches for the specified object and returns the index of the last occurrence within the entire Array. | |
LastIndexOf<T>(T[], T, Int32) | Searches for the specified object and returns the index of the last occurrence within the range of elements in the Array that extends from the first element to the specified index. | |
LastIndexOf<T>(T[], T, Int32, Int32) | Searches for the specified object and returns the index of the last occurrence within the range of elements in the Array that contains the specified number of elements and ends at the specified index. | |
MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) | |
Resize<T> | Changes the number of elements of an array to the specified new size. | |
Reverse(Array) | Reverses the sequence of the elements in the entire one-dimensional Array. | |
Reverse(Array, Int32, Int32) | Reverses the sequence of the elements in a range of elements in the one-dimensional Array. | |
SetValue(Object, Int32) | Sets a value to the element at the specified position in the one-dimensional Array. The index is specified as a 32-bit integer. | |
SetValue(Object, Int32[]) | Sets a value to the element at the specified position in the multidimensional Array. The indexes are specified as an array of 32-bit integers. | |
SetValue(Object, Int64) | Sets a value to the element at the specified position in the one-dimensional Array. The index is specified as a 64-bit integer. | |
SetValue(Object, Int64[]) | Sets a value to the element at the specified position in the multidimensional Array. The indexes are specified as an array of 64-bit integers. | |
SetValue(Object, Int32, Int32) | Sets a value to the element at the specified position in the two-dimensional Array. The indexes are specified as 32-bit integers. | |
SetValue(Object, Int64, Int64) | Sets a value to the element at the specified position in the two-dimensional Array. The indexes are specified as 64-bit integers. | |
SetValue(Object, Int32, Int32, Int32) | Sets a value to the element at the specified position in the three-dimensional Array. The indexes are specified as 32-bit integers. | |
SetValue(Object, Int64, Int64, Int64) | Sets a value to the element at the specified position in the three-dimensional Array. The indexes are specified as 64-bit integers. | |
Sort(Array) | Sorts the elements in an entire one-dimensional Array using the IComparable implementation of each element of the Array. | |
Sort(Array, Array) | Sorts a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable implementation of each key. | |
Sort(Array, IComparer) | Sorts the elements in a one-dimensional Array using the specified IComparer. | |
Sort(Array, Array, IComparer) | Sorts a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer. | |
Sort(Array, Int32, Int32) | Sorts the elements in a range of elements in a one-dimensional Array using the IComparable implementation of each element of the Array. | |
Sort(Array, Array, Int32, Int32) | Sorts a range of elements in a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable implementation of each key. | |
Sort(Array, Int32, Int32, IComparer) | Sorts the elements in a range of elements in a one-dimensional Array using the specified IComparer. | |
Sort(Array, Array, Int32, Int32, IComparer) | Sorts a range of elements in a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer. | |
Sort<T>(T[]) | Sorts the elements in an entire Array using the IComparable<T> generic interface implementation of each element of the Array. | |
Sort<T>(T[], IComparer<T>) | Sorts the elements in an Array using the specified IComparer<T> generic interface. | |
Sort<T>(T[], Comparison<T>) | Sorts the elements in an Array using the specified Comparison<T>. | |
Sort<T>(T[], Int32, Int32) | Sorts the elements in a range of elements in an Array using the IComparable<T> generic interface implementation of each element of the Array. | |
Sort<T>(T[], Int32, Int32, IComparer<T>) | Sorts the elements in a range of elements in an Array using the specified IComparer<T> generic interface. | |
Sort<TKey, TValue>(TKey[], TValue[]) | Sorts a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable<T> generic interface implementation of each key. | |
Sort<TKey, TValue>(TKey[], TValue[], IComparer<TKey>) | Sorts a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer<T> generic interface. | |
Sort<TKey, TValue>(TKey[], TValue[], Int32, Int32) | Sorts a range of elements in a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable<T> generic interface implementation of each key. | |
Sort<TKey, TValue>(TKey[], TValue[], Int32, Int32, IComparer<TKey>) | Sorts a range of elements in a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer<T> generic interface. | |
ToString | Returns a string that represents the current object. (Inherited from Object.) | |
TrueForAll<T> | Determines whether every element in the array matches the conditions defined by the specified predicate. |
Name | Description | |
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AsParallel | Enables parallelization of a query. (Defined by ParallelEnumerable.) | |
AsQueryable | Converts an IEnumerable to an IQueryable. (Defined by Queryable.) | |
Cast<TResult> | Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.) | |
OfType<TResult> | Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.) |
Name | Description | |
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ICollection.CopyTo | Copies the elements of the Array to another Array, starting at the specified index. | |
ICollection.Count | Gets the number of elements contained in the Array. | |
ICollection.IsSynchronized | Gets a value that indicates whether access to the Array is synchronized (thread safe). | |
ICollection.SyncRoot | Gets an object that can be used to synchronize access to the Array. | |
IList.Add | Adds an item to IList. | |
IList.Clear | Removes all items from the IList. | |
IList.Contains | Determines whether an element is in the IList. | |
IList.IndexOf | Determines the index of a specific item in the IList. | |
IList.Insert | Inserts an item to the IList at the specified index. | |
IList.IsFixedSize | Gets a value that indicates whether the Array has a fixed size. | |
IList.IsReadOnly | Gets a value that indicates whether the Array is read-only. | |
IList.Item | Gets or sets the element at the specified index. | |
IList.Remove | Removes the first occurrence of a specific object from the IList. | |
IList.RemoveAt | Removes the IList item at the specified index. | |
IStructuralComparable.CompareTo | Determines whether the current collection object precedes, occurs in the same position as, or follows another object in the sort order. | |
IStructuralEquatable.Equals | Determines whether an object is equal to the current instance. | |
IStructuralEquatable.GetHashCode | Returns a hash code for the current instance. |
The Array class is the base class for language implementations that support arrays. However, only the system and compilers can derive explicitly from the Array class. Users should employ the array constructs provided by the language.
An element is a value in an Array. The length of an Array is the total number of elements it can contain. The rank of an Array is the number of dimensions in the Array. The lower bound of a dimension of an Array is the starting index of that dimension of the Array; a multidimensional Array can have different bounds for each dimension. An array can have a maximum of 32 dimensions.
Important |
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In the .NET Framework version 2.0, the Array class implements the System.Collections.Generic.IList<T>, System.Collections.Generic.ICollection<T>, and System.Collections.Generic.IEnumerable<T> generic interfaces. The implementations are provided to arrays at run time, and therefore are not visible to the documentation build tools. As a result, the generic interfaces do not appear in the declaration syntax for the Array class, and there are no reference topics for interface members that are accessible only by casting an array to the generic interface type (explicit interface implementations). The key thing to be aware of when you cast an array to one of these interfaces is that members which add, insert, or remove elements throw NotSupportedException. |
Type objects provide information about array type declarations. Array objects with the same array type share the same Type object.
Type.IsArray and Type.GetElementType might not return the expected results with Array because if an array is cast to the type Array, the result is an object, not an array. That is, typeof(System.Array).IsArray returns false, and typeof(System.Array).GetElementType returns null.
Unlike most classes, Array provides the CreateInstance method, instead of public constructors, to allow for late bound access.
The Array.Copy method copies elements not only between arrays of the same type but also between standard arrays of different types; it handles type casting automatically.
Some methods, such as CreateInstance, Copy, CopyTo, GetValue, and SetValue, provide overloads that accept 64-bit integers as parameters to accommodate large capacity arrays. LongLength and GetLongLength return 64-bit integers indicating the length of the array.
The Array is not guaranteed to be sorted. You must sort the Array prior to performing operations (such as BinarySearch) that require the Array to be sorted.
Using an Array object of pointers in native code is not supported and will throw a NotSupportedException for several methods.
The following code example shows how Array.Copy copies elements between an array of type integer and an array of type Object.
public class SamplesArray { public static void Main() { // Creates and initializes a new integer array and a new Object array. int[] myIntArray = new int[5] { 1, 2, 3, 4, 5 }; Object[] myObjArray = new Object[5] { 26, 27, 28, 29, 30 }; // Prints the initial values of both arrays. Console.WriteLine( "Initially," ); Console.Write( "integer array:" ); PrintValues( myIntArray ); Console.Write( "Object array: " ); PrintValues( myObjArray ); // Copies the first two elements from the integer array to the Object array. System.Array.Copy( myIntArray, myObjArray, 2 ); // Prints the values of the modified arrays. Console.WriteLine( "\nAfter copying the first two elements of the integer array to the Object array," ); Console.Write( "integer array:" ); PrintValues( myIntArray ); Console.Write( "Object array: " ); PrintValues( myObjArray ); // Copies the last two elements from the Object array to the integer array. System.Array.Copy( myObjArray, myObjArray.GetUpperBound(0) - 1, myIntArray, myIntArray.GetUpperBound(0) - 1, 2 ); // Prints the values of the modified arrays. Console.WriteLine( "\nAfter copying the last two elements of the Object array to the integer array," ); Console.Write( "integer array:" ); PrintValues( myIntArray ); Console.Write( "Object array: " ); PrintValues( myObjArray ); } public static void PrintValues( Object[] myArr ) { foreach ( Object i in myArr ) { Console.Write( "\t{0}", i ); } Console.WriteLine(); } public static void PrintValues( int[] myArr ) { foreach ( int i in myArr ) { Console.Write( "\t{0}", i ); } Console.WriteLine(); } } /* This code produces the following output. Initially, integer array: 1 2 3 4 5 Object array: 26 27 28 29 30 After copying the first two elements of the integer array to the Object array, integer array: 1 2 3 4 5 Object array: 1 2 28 29 30 After copying the last two elements of the Object array to the integer array, integer array: 1 2 3 29 30 Object array: 1 2 28 29 30 */
The following code example creates and initializes an Array and displays its properties and its elements.
public class SamplesArray2{ public static void Main() { // Creates and initializes a new three-dimensional Array of type Int32. Array myArr = Array.CreateInstance( typeof(Int32), 2, 3, 4 ); for ( int i = myArr.GetLowerBound(0); i <= myArr.GetUpperBound(0); i++ ) for ( int j = myArr.GetLowerBound(1); j <= myArr.GetUpperBound(1); j++ ) for ( int k = myArr.GetLowerBound(2); k <= myArr.GetUpperBound(2); k++ ) { myArr.SetValue( (i*100)+(j*10)+k, i, j, k ); } // Displays the properties of the Array. Console.WriteLine( "The Array has {0} dimension(s) and a total of {1} elements.", myArr.Rank, myArr.Length ); Console.WriteLine( "\tLength\tLower\tUpper" ); for ( int i = 0; i < myArr.Rank; i++ ) { Console.Write( "{0}:\t{1}", i, myArr.GetLength(i) ); Console.WriteLine( "\t{0}\t{1}", myArr.GetLowerBound(i), myArr.GetUpperBound(i) ); } // Displays the contents of the Array. Console.WriteLine( "The Array contains the following values:" ); PrintValues( myArr ); } public static void PrintValues( Array myArr ) { System.Collections.IEnumerator myEnumerator = myArr.GetEnumerator(); int i = 0; int cols = myArr.GetLength( myArr.Rank - 1 ); while ( myEnumerator.MoveNext() ) { if ( i < cols ) { i++; } else { Console.WriteLine(); i = 1; } Console.Write( "\t{0}", myEnumerator.Current ); } Console.WriteLine(); } } /* This code produces the following output. The Array has 3 dimension(s) and a total of 24 elements. Length Lower Upper 0: 2 0 1 1: 3 0 2 2: 4 0 3 The Array contains the following values: 0 1 2 3 10 11 12 13 20 21 22 23 100 101 102 103 110 111 112 113 120 121 122 123 */
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
This implementation does not provide a synchronized (thread safe) wrapper for an Array; however, .NET Framework classes based on Array provide their own synchronized version of the collection using the SyncRoot property.
Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.