langreiter.com plain, simple: LINQ

LANGREITER.COM plain, simple

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LINQ

CREATED BY chris • LAST EDITED BY chris 6956 days AGO

Language-integrated Query

msdn.microsoft.com/vcsharp/future/linqsamples/

blogs.msdn.com/danielfe/archive/2005/09/13/464904.aspx

System.Query.Func?

The "Standard Query Operators" (extension methods extending IEnumerable<T>) are declared in [create System.Query.Sequence]; they form a query language for collections. .

Standard Query Operators

Selection

Where
boolean p( x )
boolean p( x, i )
persons.Where( p => p.Age >= 26 );

Projection

Select (map?)
f( x )
f( x, i )
persons.Select( p => new { p.FirstName, p.LastName } );

SelectMany
f( x )
f( x, i )
orders = customers.Select( c => c.Orders );

Partition

Take
f( n )

Skip
f( n )

TakeWhile
bool p( x )
bool p( x, i )

SkipWhile
bool p( x )
bool p( x, i )

Concatenation

Concat
foo.Concat( bar );
Alternately: SelectMany w/ identity selector.

Ordering

OrderBy/ThenBy

Reverse

Grouping

GroupBy

Set

Distinct

Union

Intersect

Except

Conversion

ToSequence

ToArray

ToList

ToDictionary

OfType

Equality

EqualAll

Element

First
none
bool p( x )
bool p( x, i )

FirstOrDefault
none
bool p( x )
bool p( x, i )

ElementAt
i

Generation

Range
start, n

Repeat
x, n

Quantifiers

Any

All

Aggregate

Count

Sum

Min

Max

Average

Fold

p - predicate, x - element, i - index, n - count.