Method Segment

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

Divides a sequence into multiple sequences by using a segment detector based on the original sequence

Declaration
public static IEnumerable<IReadOnlyList<T>> Segment<T>(this IEnumerable<T> source, Func<T, bool> newSegmentPredicate)
Parameters
Type Name Description
IEnumerable<T> source

The sequence to segment
Func<T, bool> newSegmentPredicate

A function, which returns true if the given element begins a new segment, and false otherwise
Returns
Type Description
IEnumerable<IReadOnlyList<T>>

A sequence of segment, each of which is a portion of the original sequence
Type Parameters
Name Description
T

The type of the elements in the sequence
Remarks

This method is implemented by using deferred execution and streams the groupings. The grouping elements, however, are buffered. Each grouping is therefore yielded as soon as it is complete and before the next grouping occurs.

Examples

The following code example demonstrates how to split a sequence based on a segment detector using Segment.

var sequence = new[]
{
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 789),
    (key: "feb", value: 987),
    (key: "Feb", value: 654),
    (key: "FEB", value: 321),
    (key: "mar", value: 789),
    (key: "Mar", value: 456),
    (key: "MAR", value: 123),
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 781),
};

// Group adjacent items
var result = sequence
    .Segment(
        x => x.key[0] == 'm');

Console.WriteLine(
    "[" + Environment.NewLine + 
    string.Join(
        ", " + Environment.NewLine, 
        result.Select(c => "   [" + string.Join(", ", c) + "]")) +
    Environment.NewLine + "]");

// This code produces the following output:
// [
//    [(jan, 123), (Jan, 456), (JAN, 789), (feb, 987), (Feb, 654), (FEB, 321)],
//    [(mar, 789), (Mar, 456), (MAR, 123), (jan, 123), (Jan, 456), (JAN, 781)]
// ]
Exceptions
Type Condition
ArgumentNullException

source or newSegmentPredicate is null.
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Segment<T>(IEnumerable<T>, Func<T, int, bool>)

Divides a sequence into multiple sequences by using a segment detector based on the original sequence

Declaration
public static IEnumerable<IReadOnlyList<T>> Segment<T>(this IEnumerable<T> source, Func<T, int, bool> newSegmentPredicate)
Parameters
Type Name Description
IEnumerable<T> source

The sequence to segment
Func<T, int, bool> newSegmentPredicate

A function, which returns true if the given element and index begins a new segment, and false otherwise
Returns
Type Description
IEnumerable<IReadOnlyList<T>>

A sequence of segment, each of which is a portion of the original sequence
Type Parameters
Name Description
T

The type of the elements in the sequence
Remarks

This method is implemented by using deferred execution and streams the groupings. The grouping elements, however, are buffered. Each grouping is therefore yielded as soon as it is complete and before the next grouping occurs.

Examples

The following code example demonstrates how to split a sequence based on a segment detector using Segment.

var sequence = new[]
{
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 789),
    (key: "feb", value: 987),
    (key: "Feb", value: 654),
    (key: "FEB", value: 321),
    (key: "mar", value: 789),
    (key: "Mar", value: 456),
    (key: "MAR", value: 123),
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 781),
};

// Group adjacent items
var result = sequence
    .Segment(
        (x, i) => i % 3 == 0);

Console.WriteLine(
    "[" + Environment.NewLine + 
    string.Join(
        ", " + Environment.NewLine, 
        result.Select(c => "   [" + string.Join(", ", c) + "]")) +
    Environment.NewLine + "]");

// This code produces the following output:
// [
//    [(jan, 123), (Jan, 456), (JAN, 789)],
//    [(feb, 987), (Feb, 654), (FEB, 321)],
//    [(mar, 789), (Mar, 456), (MAR, 123)],
//    [(jan, 123), (Jan, 456), (JAN, 781)]
// ]
Exceptions
Type Condition
ArgumentNullException

source or newSegmentPredicate is null.
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Segment<T>(IEnumerable<T>, Func<T, T, int, bool>)

Divides a sequence into multiple sequences by using a segment detector based on the original sequence

Declaration
public static IEnumerable<IReadOnlyList<T>> Segment<T>(this IEnumerable<T> source, Func<T, T, int, bool> newSegmentPredicate)
Parameters
Type Name Description
IEnumerable<T> source

The sequence to segment
Func<T, T, int, bool> newSegmentPredicate

A function, which returns true if the given current element, previous element, and index begins a new segment, and false otherwise
Returns
Type Description
IEnumerable<IReadOnlyList<T>>

A sequence of segment, each of which is a portion of the original sequence
Type Parameters
Name Description
T

The type of the elements in the sequence
Remarks

This method is implemented by using deferred execution and streams the groupings. The grouping elements, however, are buffered. Each grouping is therefore yielded as soon as it is complete and before the next grouping occurs.

Examples

The following code example demonstrates how to split a sequence based on a segment detector using Segment.

var sequence = new[]
{
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 789),
    (key: "feb", value: 987),
    (key: "Feb", value: 654),
    (key: "FEB", value: 321),
    (key: "mar", value: 789),
    (key: "Mar", value: 456),
    (key: "MAR", value: 123),
    (key: "jan", value: 123),
    (key: "Jan", value: 456),
    (key: "JAN", value: 781),
};

// Group adjacent items
var result = sequence
    .Segment(
        (cur, prev, i) => !string.Equals(cur.key[..1], prev.key[..1], StringComparison.OrdinalIgnoreCase));

Console.WriteLine(
    "[" + Environment.NewLine + 
    string.Join(
        ", " + Environment.NewLine, 
        result.Select(c => "   [" + string.Join(", ", c) + "]")) +
    Environment.NewLine + "]");

// This code produces the following output:
// [
//    [(jan, 123), (Jan, 456), (JAN, 789)],
//    [(feb, 987), (Feb, 654), (FEB, 321)],
//    [(mar, 789), (Mar, 456), (MAR, 123)],
//    [(jan, 123), (Jan, 456), (JAN, 781)]
// ]
Exceptions
Type Condition
ArgumentNullException

source or newSegmentPredicate is null.