Collection<T>.Contains(T) Method
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Determines whether an element is in the Collection<T>.
public:
virtual bool Contains(T item);
public bool Contains (T item);
abstract member Contains : 'T -> bool
override this.Contains : 'T -> bool
Public Function Contains (item As T) As Boolean
- item
- T
The object to locate in the Collection<T>. The value can be null
for reference types.
true
if item
is found in the Collection<T>; otherwise, false
.
If the Collection<T> object is created using the parameterless constructor, this method determines equality using the default equality comparer EqualityComparer<T>.Default for T
, the type of values in the list. If type T
does not implement the IEquatable<T> interface, the Equals method is used.
If the Collection object is created by passing an IList<T> object to the constructor, the Contains method will be determined by the IEqualityComparer<T> interface used by that IList<T> object.
This method performs a linear search; therefore, the average execution time is proportional to Count. That is, this method is an O(n
) operation, where n
is Count.
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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