Method Partition

Partition<T>(IEnumerable<T>, Func<T, bool>)

Partitions or splits a sequence in two using a predicate.

Declaration

public static (IEnumerable<T> True, IEnumerable<T> False) Partition<T>(this IEnumerable<T> source, Func<T, bool> predicate)

Parameters

Type	Name	Description
IEnumerable<T>	source	The source sequence.
Func<T, bool>	predicate	The predicate function.

Returns

Type	Description
(IEnumerable<T> True, IEnumerable<T> False)	A tuple of elements satisfying the predicate and those that do not, respectively.

Type Parameters

Name	Description
T	Type of source elements.

Remarks

This method executes immediately.

Examples

The following code example demonstrates how to partition a sequence using Partition.

var sequence = Enumerable.Range(0, 10);

// Partition a sequence
var (evens, odds) = sequence
    .Partition(x => x % 2 == 0);

Console.WriteLine(
    "evens: [" +
    string.Join(", ", evens) +
    "]");

Console.WriteLine(
    "odds: [" +
    string.Join(", ", odds) +
    "]");

// This code produces the following output:
// evens: [0, 2, 4, 6, 8]
// odds: [1, 3, 5, 7, 9]

Exceptions

Type	Condition
ArgumentNullException	source is null.

Partition<T, TResult>(IEnumerable<T>, Func<T, bool>, Func<IEnumerable<T>, IEnumerable<T>, TResult>)

Partitions or splits a sequence in two using a predicate and then projects a result from the two.

Declaration

public static TResult Partition<T, TResult>(this IEnumerable<T> source, Func<T, bool> predicate, Func<IEnumerable<T>, IEnumerable<T>, TResult> resultSelector)

Parameters

Type	Name	Description
IEnumerable<T>	source	The source sequence.
Func<T, bool>	predicate	The predicate function.
Func<IEnumerable<T>, IEnumerable<T>, TResult>	resultSelector	Function that projects the result from sequences of elements that satisfy the predicate and those that do not, respectively, passed as arguments.

Returns

Type	Description
TResult	The return value from resultSelector.

Type Parameters

Name	Description
T	Type of source elements.
TResult	Type of the result.

Remarks

This method executes immediately.

Examples

The following code example demonstrates how to partition a sequence using Partition.

var sequence = Enumerable.Range(0, 10);

// Partition a sequence
var (evens, odds) = sequence
    .Partition(x => x % 2 == 0, ValueTuple.Create);

Console.WriteLine(
    "evens: [" +
    string.Join(", ", evens) +
    "]");

Console.WriteLine(
    "odds: [" +
    string.Join(", ", odds) +
    "]");

// This code produces the following output:
// evens: [0, 2, 4, 6, 8]
// odds: [1, 3, 5, 7, 9]

Exceptions

Type	Condition
ArgumentNullException	source, predicate, or resultSelector is null.