Linq Extensions.To Lookup Method
Definition
Namespace: Numerics.NET.DataAnalysis.Linq
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.2
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.0.2
Overload List
ToLookup<T, TKey>(Vector<T>, Func<T, TKey>) | Creates a lookup from a vector according to the specified key selector function. |
ToLookup<T, TKey>(Vector<T>, Func<T, TKey>, IEqualityComparer<TKey>) | Creates a lookup from a vector according to the specified key selector function and key comparer. |
ToLookup<R, C, TKey>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>) | Creates a lookup for the data frame according to the specified key selector function. |
ToLookup<R, C, TKey>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, IEqualityComparer<TKey>) | Creates a lookup for the data frame according to the specified key selector function and key comparer. |
ToLookup<T, TKey, TElement>(Vector<T>, Func<T, TKey>, Func<T, TElement>) | Creates a lookup from a vector according to the specified key selector and element selector functions. |
ToLookup<T, TKey, TElement>(Vector<T>, Func<T, TKey>, Func<T, TElement>, IEqualityComparer<TKey>) | Creates a lookup from a vector according to the specified key selector and element selector functions, and key comparer. |
ToLookup<R, C, TKey, TElement>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, Func<DataFrameRow<R, C>, TElement>) | Creates a lookup for the data frame according to the specified key selector and element selector function. |
ToLookup<R, C, TKey, TElement>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, Func<DataFrameRow<R, C>, TElement>, IEqualityComparer<TKey>) | Creates a lookup for the data frame according to the specified key selector and element selector function. |
ToLookup<R, C, TKey>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>)
Creates a lookup for the data frame according to the specified key selector function.
public static LinqExtensions.DataFrameLookup<TKey, R, C> ToLookup<R, C, TKey>(
this DataFrame<R, C> frame,
Func<DataFrameRow<R, C>, TKey> keySelector
)
Parameters
- frame DataFrame<R, C>
- A data frame to project.
- keySelector Func<DataFrameRow<R, C>, TKey>
- A function to extract a key from each row.
Type Parameters
- R
- The element type of the row index of the data frame.
- C
- The element type of the column index of the data frame.
- TKey
- The type of the key returned by keySelector.
Return Value
LinqExtensions.DataFrameLookup<TKey, R, C>A LinqExtensions.Lookup<TKey, T> that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type DataFrame<R, C>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Exceptions
Argument | frame is null. -or- keySelector is null. |
ToLookup<T, TKey>(Vector<T>, Func<T, TKey>)
Creates a lookup from a vector according to the specified key selector function.
public static LinqExtensions.Lookup<TKey, T> ToLookup<T, TKey>(
this Vector<T> vector,
Func<T, TKey> keySelector
)
Parameters
- vector Vector<T>
- The vector to create a lookup from.
- keySelector Func<T, TKey>
- A function to extract a key from each element.
Type Parameters
- T
- The type of the elements of the vector.
- TKey
- The type of the key returned by the key selector.
Return Value
LinqExtensions.Lookup<TKey, T>A lookup that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type Vector<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).ToLookup<R, C, TKey>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, IEqualityComparer<TKey>)
Creates a lookup for the data frame according to the specified key selector function
and key comparer.
public static LinqExtensions.DataFrameLookup<TKey, R, C> ToLookup<R, C, TKey>(
this DataFrame<R, C> frame,
Func<DataFrameRow<R, C>, TKey> keySelector,
IEqualityComparer<TKey> comparer
)
Parameters
- frame DataFrame<R, C>
- A data frame to project.
- keySelector Func<DataFrameRow<R, C>, TKey>
- A function to extract a key from each row.
- comparer IEqualityComparer<TKey>
- An IEqualityComparer<T> to compare keys.
Type Parameters
- R
- The element type of the row index of the data frame.
- C
- The element type of the column index of the data frame.
- TKey
- The type of the key returned by keySelector.
Return Value
LinqExtensions.DataFrameLookup<TKey, R, C>A LinqExtensions.Lookup<TKey, T> that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type DataFrame<R, C>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Remarks
If comparer is null, the Default is used to compare keys.
Exceptions
Argument | frame is null. -or- keySelector is null. |
ToLookup<R, C, TKey, TElement>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, Func<DataFrameRow<R, C>, TElement>)
Creates a lookup for the data frame according to the specified key selector
and element selector function.
public static LinqExtensions.Lookup<TKey, TElement> ToLookup<R, C, TKey, TElement>(
this DataFrame<R, C> frame,
Func<DataFrameRow<R, C>, TKey> keySelector,
Func<DataFrameRow<R, C>, TElement> elementSelector
)
Parameters
- frame DataFrame<R, C>
- A data frame to project.
- keySelector Func<DataFrameRow<R, C>, TKey>
- A function to extract a key from each row.
- elementSelector Func<DataFrameRow<R, C>, TElement>
- A function that transforms each row into a result.
Type Parameters
- R
- The element type of the row index of the data frame.
- C
- The element type of the column index of the data frame.
- TKey
- The type of the key returned by keySelector.
- TElement
- The type of the result returned by elementSelector.
Return Value
LinqExtensions.Lookup<TKey, TElement>A LinqExtensions.Lookup<TKey, T> that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type DataFrame<R, C>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Exceptions
Argument | frame is null. -or- keySelector is null. -or- elementSelector is null. |
ToLookup<T, TKey>(Vector<T>, Func<T, TKey>, IEqualityComparer<TKey>)
Creates a lookup from a vector according to the specified
key selector function and key comparer.
public static LinqExtensions.Lookup<TKey, T> ToLookup<T, TKey>(
this Vector<T> vector,
Func<T, TKey> keySelector,
IEqualityComparer<TKey> comparer
)
Parameters
- vector Vector<T>
- The vector to create a lookup from.
- keySelector Func<T, TKey>
- A function to extract a key from each element.
- comparer IEqualityComparer<TKey>
- An object that compares two keys for equality.
Type Parameters
- T
- The type of the elements of the vector.
- TKey
- The type of the key returned by the key selector.
Return Value
LinqExtensions.Lookup<TKey, T>A lookup that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type Vector<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).ToLookup<T, TKey, TElement>(Vector<T>, Func<T, TKey>, Func<T, TElement>)
Creates a lookup from a vector according to the specified
key selector and element selector functions.
public static LinqExtensions.Lookup<TKey, TElement> ToLookup<T, TKey, TElement>(
this Vector<T> vector,
Func<T, TKey> keySelector,
Func<T, TElement> elementSelector
)
Parameters
- vector Vector<T>
- The vector to create a lookup from.
- keySelector Func<T, TKey>
- A function to extract a key from each element.
- elementSelector Func<T, TElement>
- A function that transforms each input element.
Type Parameters
- T
- The type of the elements of the vector.
- TKey
- The type of the key returned by the key selector.
- TElement
- The type of the value returned by the element selector.
Return Value
LinqExtensions.Lookup<TKey, TElement>A lookup that contains keys and values selected from the input using elementSelector.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type Vector<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).ToLookup<R, C, TKey, TElement>(DataFrame<R, C>, Func<DataFrameRow<R, C>, TKey>, Func<DataFrameRow<R, C>, TElement>, IEqualityComparer<TKey>)
Creates a lookup for the data frame according to the specified key selector
and element selector function.
public static LinqExtensions.Lookup<TKey, TElement> ToLookup<R, C, TKey, TElement>(
this DataFrame<R, C> frame,
Func<DataFrameRow<R, C>, TKey> keySelector,
Func<DataFrameRow<R, C>, TElement> elementSelector,
IEqualityComparer<TKey> comparer
)
Parameters
- frame DataFrame<R, C>
- A data frame to project.
- keySelector Func<DataFrameRow<R, C>, TKey>
- A function to extract a key from each row.
- elementSelector Func<DataFrameRow<R, C>, TElement>
- A function that transforms each row into a result.
- comparer IEqualityComparer<TKey>
- An IEqualityComparer<T> to compare keys.
Type Parameters
- R
- The element type of the row index of the data frame.
- C
- The element type of the column index of the data frame.
- TKey
- The type of the key returned by keySelector.
- TElement
- The type of the result returned by elementSelector.
Return Value
LinqExtensions.Lookup<TKey, TElement>A LinqExtensions.Lookup<TKey, T> that contains keys and values.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type DataFrame<R, C>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).Remarks
If comparer is null, the Default is used to compare keys.
Exceptions
Argument | frame is null. -or- keySelector is null. -or- elementSelector is null. |
ToLookup<T, TKey, TElement>(Vector<T>, Func<T, TKey>, Func<T, TElement>, IEqualityComparer<TKey>)
Creates a lookup from a vector according to the specified
key selector and element selector functions, and key comparer.
public static LinqExtensions.Lookup<TKey, TElement> ToLookup<T, TKey, TElement>(
this Vector<T> vector,
Func<T, TKey> keySelector,
Func<T, TElement> elementSelector,
IEqualityComparer<TKey> comparer
)
Parameters
- vector Vector<T>
- The vector to create a lookup from.
- keySelector Func<T, TKey>
- A function to extract a key from each element.
- elementSelector Func<T, TElement>
- A function that transforms each input element.
- comparer IEqualityComparer<TKey>
- An object that compares two keys for equality.
Type Parameters
- T
- The type of the elements of the vector.
- TKey
- The type of the key returned by the key selector.
- TElement
- The type of the value returned by the element selector.
Return Value
LinqExtensions.Lookup<TKey, TElement>A lookup that contains keys and values selected from the input using elementSelector.