Enumerable Class
 
System_CAPS_noteNote

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Provides a set of static (Shared in Visual Basic) methods for querying objects that implement IEnumerable.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

SystemObject
  System.LinqEnumerable

public static class Enumerable
[ExtensionAttribute]
public ref class Enumerable abstract sealed 
[<AbstractClass>]
[<Sealed>]
type Enumerable = class end
<ExtensionAttribute>
Public NotInheritable Class Enumerable
NameDescription
System_CAPS_pubmethod System_CAPS_static Aggregate

Applies an accumulator function over a sequence.

System_CAPS_pubmethod System_CAPS_static Aggregate

Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.

System_CAPS_pubmethod System_CAPS_static Aggregate

Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

System_CAPS_pubmethod System_CAPS_static All

Determines whether all elements of a sequence satisfy a condition.

System_CAPS_pubmethod System_CAPS_static Any

Determines whether a sequence contains any elements.

System_CAPS_pubmethod System_CAPS_static Any

Determines whether any element of a sequence satisfies a condition.

System_CAPS_pubmethod System_CAPS_static Append

Appends a value to the end of the sequence.

System_CAPS_pubmethod System_CAPS_static AsEnumerable

Returns the input typed as IEnumerable.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Decimal values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Double values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Int32 values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Int64 values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Decimal values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Double values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Int32 values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Int64 values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Single values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Single values.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Average

Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Cast

Casts the elements of an IEnumerable to the specified type.

System_CAPS_pubmethod System_CAPS_static Concat

Concatenates two sequences.

System_CAPS_pubmethod System_CAPS_static Contains

Determines whether a sequence contains a specified element by using the default equality comparer.

System_CAPS_pubmethod System_CAPS_static Contains

Determines whether a sequence contains a specified element by using a specified IEqualityComparer.

System_CAPS_pubmethod System_CAPS_static Count

Returns the number of elements in a sequence.

System_CAPS_pubmethod System_CAPS_static Count

Returns a number that represents how many elements in the specified sequence satisfy a condition.

System_CAPS_pubmethod System_CAPS_static DefaultIfEmpty

Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty.

System_CAPS_pubmethod System_CAPS_static DefaultIfEmpty

Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.

System_CAPS_pubmethod System_CAPS_static Distinct

Returns distinct elements from a sequence by using the default equality comparer to compare values.

System_CAPS_pubmethod System_CAPS_static Distinct

Returns distinct elements from a sequence by using a specified IEqualityComparer to compare values.

System_CAPS_pubmethod System_CAPS_static ElementAt

Returns the element at a specified index in a sequence.

System_CAPS_pubmethod System_CAPS_static ElementAtOrDefault

Returns the element at a specified index in a sequence or a default value if the index is out of range.

System_CAPS_pubmethod System_CAPS_static Empty

Returns an empty IEnumerable that has the specified type argument.

System_CAPS_pubmethod System_CAPS_static Except

Produces the set difference of two sequences by using the default equality comparer to compare values.

System_CAPS_pubmethod System_CAPS_static Except

Produces the set difference of two sequences by using the specified IEqualityComparer to compare values.

System_CAPS_pubmethod System_CAPS_static First

Returns the first element of a sequence.

System_CAPS_pubmethod System_CAPS_static First

Returns the first element in a sequence that satisfies a specified condition.

System_CAPS_pubmethod System_CAPS_static FirstOrDefault

Returns the first element of a sequence, or a default value if the sequence contains no elements.

System_CAPS_pubmethod System_CAPS_static FirstOrDefault

Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a key selector function. The keys are compared by using a comparer and each group's elements are projected by using a specified function.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The keys are compared by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function.

System_CAPS_pubmethod System_CAPS_static GroupBy

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function.

System_CAPS_pubmethod System_CAPS_static GroupJoin

Correlates the elements of two sequences based on equality of keys and groups the results. The default equality comparer is used to compare keys.

System_CAPS_pubmethod System_CAPS_static GroupJoin

Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer is used to compare keys.

System_CAPS_pubmethod System_CAPS_static Intersect

Produces the set intersection of two sequences by using the default equality comparer to compare values.

System_CAPS_pubmethod System_CAPS_static Intersect

Produces the set intersection of two sequences by using the specified IEqualityComparer to compare values.

System_CAPS_pubmethod System_CAPS_static Join

Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys.

System_CAPS_pubmethod System_CAPS_static Join

Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer is used to compare keys.

System_CAPS_pubmethod System_CAPS_static Last

Returns the last element of a sequence.

System_CAPS_pubmethod System_CAPS_static Last

Returns the last element of a sequence that satisfies a specified condition.

System_CAPS_pubmethod System_CAPS_static LastOrDefault

Returns the last element of a sequence, or a default value if the sequence contains no elements.

System_CAPS_pubmethod System_CAPS_static LastOrDefault

Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.

System_CAPS_pubmethod System_CAPS_static LongCount

Returns an Int64 that represents the total number of elements in a sequence.

System_CAPS_pubmethod System_CAPS_static LongCount

Returns an Int64 that represents how many elements in a sequence satisfy a condition.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of Decimal values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of Double values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of Int32 values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of Int64 values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of nullable Decimal values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of nullable Double values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of nullable Int32 values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of nullable Int64 values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of nullable Single values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a sequence of Single values.

System_CAPS_pubmethod System_CAPS_static Max

Returns the maximum value in a generic sequence.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum Decimal value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum Double value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum Int32 value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum Int64 value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum nullable Decimal value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum nullable Double value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum nullable Int32 value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum nullable Single value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a sequence and returns the maximum Single value.

System_CAPS_pubmethod System_CAPS_static Max

Invokes a transform function on each element of a generic sequence and returns the maximum resulting value.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of Decimal values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of Double values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of Int32 values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of Int64 values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of nullable Decimal values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of nullable Double values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of nullable Int32 values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of nullable Int64 values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of nullable Single values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a sequence of Single values.

System_CAPS_pubmethod System_CAPS_static Min

Returns the minimum value in a generic sequence.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum Decimal value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum Double value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum Int32 value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum Int64 value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum nullable Decimal value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum nullable Double value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum nullable Int32 value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum nullable Int64 value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum nullable Single value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a sequence and returns the minimum Single value.

System_CAPS_pubmethod System_CAPS_static Min

Invokes a transform function on each element of a generic sequence and returns the minimum resulting value.

System_CAPS_pubmethod System_CAPS_static OfType

Filters the elements of an IEnumerable based on a specified type.

System_CAPS_pubmethod System_CAPS_static OrderBy

Sorts the elements of a sequence in ascending order according to a key.

System_CAPS_pubmethod System_CAPS_static OrderBy

Sorts the elements of a sequence in ascending order by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static OrderByDescending

Sorts the elements of a sequence in descending order according to a key.

System_CAPS_pubmethod System_CAPS_static OrderByDescending

Sorts the elements of a sequence in descending order by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static Prepend

Adds a value to the beginning of the sequence.

System_CAPS_pubmethod System_CAPS_static Range

Generates a sequence of integral numbers within a specified range.

System_CAPS_pubmethod System_CAPS_static Repeat

Generates a sequence that contains one repeated value.

System_CAPS_pubmethod System_CAPS_static Reverse

Inverts the order of the elements in a sequence.

System_CAPS_pubmethod System_CAPS_static Select

Projects each element of a sequence into a new form.

System_CAPS_pubmethod System_CAPS_static Select

Projects each element of a sequence into a new form by incorporating the element's index.

System_CAPS_pubmethod System_CAPS_static SelectMany

Projects each element of a sequence to an IEnumerable and flattens the resulting sequences into one sequence.

System_CAPS_pubmethod System_CAPS_static SelectMany

Projects each element of a sequence to an IEnumerable, and flattens the resulting sequences into one sequence. The index of each source element is used in the projected form of that element.

System_CAPS_pubmethod System_CAPS_static SelectMany

Projects each element of a sequence to an IEnumerable, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein.

System_CAPS_pubmethod System_CAPS_static SelectMany

Projects each element of a sequence to an IEnumerable, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. The index of each source element is used in the intermediate projected form of that element.

System_CAPS_pubmethod System_CAPS_static SequenceEqual

Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

System_CAPS_pubmethod System_CAPS_static SequenceEqual

Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer.

System_CAPS_pubmethod System_CAPS_static Single

Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.

System_CAPS_pubmethod System_CAPS_static Single

Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

System_CAPS_pubmethod System_CAPS_static SingleOrDefault

Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

System_CAPS_pubmethod System_CAPS_static SingleOrDefault

Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

System_CAPS_pubmethod System_CAPS_static Skip

Bypasses a specified number of elements in a sequence and then returns the remaining elements.

System_CAPS_pubmethod System_CAPS_static SkipWhile

Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

System_CAPS_pubmethod System_CAPS_static SkipWhile

Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. The element's index is used in the logic of the predicate function.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of Decimal values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of Double values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of Int32 values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of Int64 values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of nullable Decimal values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of nullable Double values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of nullable Int32 values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of nullable Int64 values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of nullable Single values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of a sequence of Single values.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Sum

Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

System_CAPS_pubmethod System_CAPS_static Take

Returns a specified number of contiguous elements from the start of a sequence.

System_CAPS_pubmethod System_CAPS_static TakeWhile

Returns elements from a sequence as long as a specified condition is true.

System_CAPS_pubmethod System_CAPS_static TakeWhile

Returns elements from a sequence as long as a specified condition is true. The element's index is used in the logic of the predicate function.

System_CAPS_pubmethod System_CAPS_static ThenBy

Performs a subsequent ordering of the elements in a sequence in ascending order according to a key.

System_CAPS_pubmethod System_CAPS_static ThenBy

Performs a subsequent ordering of the elements in a sequence in ascending order by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static ThenByDescending

Performs a subsequent ordering of the elements in a sequence in descending order, according to a key.

System_CAPS_pubmethod System_CAPS_static ThenByDescending

Performs a subsequent ordering of the elements in a sequence in descending order by using a specified comparer.

System_CAPS_pubmethod System_CAPS_static ToArray

Creates an array from a IEnumerable.

System_CAPS_pubmethod System_CAPS_static ToDictionary

Creates a Dictionary from an IEnumerable according to a specified key selector function.

System_CAPS_pubmethod System_CAPS_static ToDictionary

Creates a Dictionary from an IEnumerable according to a specified key selector function and key comparer.

System_CAPS_pubmethod System_CAPS_static ToDictionary

Creates a Dictionary from an IEnumerable according to specified key selector and element selector functions.

System_CAPS_pubmethod System_CAPS_static ToDictionary

Creates a Dictionary from an IEnumerable according to a specified key selector function, a comparer, and an element selector function.

System_CAPS_pubmethod System_CAPS_static ToHashSet

Creates a HashSet from an IEnumerable.

System_CAPS_pubmethod System_CAPS_static ToHashSet

Creates a HashSet from an IEnumerable using the comparer to compare keys

System_CAPS_pubmethod System_CAPS_static ToList

Creates a List from an IEnumerable.

System_CAPS_pubmethod System_CAPS_static ToLookup

Creates a Lookup from an IEnumerable according to a specified key selector function.

System_CAPS_pubmethod System_CAPS_static ToLookup

Creates a Lookup from an IEnumerable according to a specified key selector function and key comparer.

System_CAPS_pubmethod System_CAPS_static ToLookup

Creates a Lookup from an IEnumerable according to specified key selector and element selector functions.

System_CAPS_pubmethod System_CAPS_static ToLookup

Creates a Lookup from an IEnumerable according to a specified key selector function, a comparer and an element selector function.

System_CAPS_pubmethod System_CAPS_static Union

Produces the set union of two sequences by using the default equality comparer.

System_CAPS_pubmethod System_CAPS_static Union

Produces the set union of two sequences by using a specified IEqualityComparer.

System_CAPS_pubmethod System_CAPS_static Where

Filters a sequence of values based on a predicate.

System_CAPS_pubmethod System_CAPS_static Where

Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function.

System_CAPS_pubmethod System_CAPS_static Zip

Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.

The methods in this class provide an implementation of the standard query operators for querying data sources that implement IEnumerable. The standard query operators are general purpose methods that follow the LINQ pattern and enable you to express traversal, filter, and projection operations over data in any .NET-based programming language.

The majority of the methods in this class are defined as extension methods that extend IEnumerable. This means they can be called like an instance method on any object that implements IEnumerable.

Methods that are used in a query that returns a sequence of values do not consume the target data until the query object is enumerated. This is known as deferred execution. Methods that are used in a query that returns a singleton value execute and consume the target data immediately.

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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