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Create frame from dictionaries

A simple example that creates a frame from a list of dictionaries. Each dictionary is treated as a row that maps column keys to values. The trick is to use Deedle value expansion.

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open Deedle

// Given a list of dictionaries
let d1 = dict [ "A", 1.0; "B", 3.0 ]
let d2 = dict [ "A", 2.0; "C", 10.0 ]
let ds = [ d1; d2 ]

// Create a frame with a single column named "It"
// that contains the dictionaries as values
let f = frame [ "It" => Series.ofValues ds ]

// Expand all dictionaries into multiple columns
// The resulting frame has 3 columns named
// It.A, It.B and It.C
f |> Frame.expandAllCols 1
namespace Deedle
val d1 : System.Collections.Generic.IDictionary<string,float>

Full name: Script.d1
val dict : keyValuePairs:seq<'Key * 'Value> -> System.Collections.Generic.IDictionary<'Key,'Value> (requires equality)

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.dict
val d2 : System.Collections.Generic.IDictionary<string,float>

Full name: Script.d2
val ds : System.Collections.Generic.IDictionary<string,float> list

Full name: Script.ds
val f : Frame<int,string>

Full name: Script.f
val frame : columns:seq<'a * #ISeries<'c>> -> Frame<'c,'a> (requires equality and equality)

Full name: Deedle.F# Frame extensions.frame
Multiple items
module Series

from Deedle

--------------------
type Series =
  static member ofNullables : values:seq<Nullable<'a0>> -> Series<int,'a0> (requires default constructor and value type and 'a0 :> ValueType)
  static member ofObservations : observations:seq<'a0 * 'a1> -> Series<'a0,'a1> (requires equality)
  static member ofOptionalObservations : observations:seq<'K * 'a1 option> -> Series<'K,'a1> (requires equality)
  static member ofValues : values:seq<'a> -> Series<int,'a>

Full name: Deedle.F# Series extensions.Series

--------------------
type Series<'K,'V (requires equality)> =
  interface IFsiFormattable
  interface ISeries<'K>
  new : pairs:seq<KeyValuePair<'K,'V>> -> Series<'K,'V>
  new : keys:'K [] * values:'V [] -> Series<'K,'V>
  new : keys:seq<'K> * values:seq<'V> -> Series<'K,'V>
  new : index:IIndex<'K> * vector:IVector<'V> * vectorBuilder:IVectorBuilder * indexBuilder:IIndexBuilder -> Series<'K,'V>
  member After : lowerExclusive:'K -> Series<'K,'V>
  member Aggregate : aggregation:Aggregation<'K> * observationSelector:Func<DataSegment<Series<'K,'V>>,KeyValuePair<'TNewKey,OptionalValue<'R>>> -> Series<'TNewKey,'R> (requires equality)
  member Aggregate : aggregation:Aggregation<'K> * keySelector:Func<DataSegment<Series<'K,'V>>,'TNewKey> * valueSelector:Func<DataSegment<Series<'K,'V>>,OptionalValue<'R>> -> Series<'TNewKey,'R> (requires equality)
  member AsyncMaterialize : unit -> Async<Series<'K,'V>>
  ...

Full name: Deedle.Series<_,_>

--------------------
new : pairs:seq<System.Collections.Generic.KeyValuePair<'K,'V>> -> Series<'K,'V>
new : keys:seq<'K> * values:seq<'V> -> Series<'K,'V>
new : keys:'K [] * values:'V [] -> Series<'K,'V>
new : index:Indices.IIndex<'K> * vector:IVector<'V> * vectorBuilder:Vectors.IVectorBuilder * indexBuilder:Indices.IIndexBuilder -> Series<'K,'V>
static member Series.ofValues : values:seq<'a> -> Series<int,'a>
Multiple items
module Frame

from Deedle

--------------------
type Frame =
  static member ReadReader : reader:IDataReader -> Frame<int,string>
  static member CustomExpanders : Dictionary<Type,Func<obj,seq<string * Type * obj>>>
  static member NonExpandableInterfaces : List<Type>
  static member NonExpandableTypes : HashSet<Type>

Full name: Deedle.Frame

--------------------
type Frame<'TRowKey,'TColumnKey (requires equality and equality)> =
  interface IDynamicMetaObjectProvider
  interface INotifyCollectionChanged
  interface IFsiFormattable
  interface IFrame
  new : names:seq<'TColumnKey> * columns:seq<ISeries<'TRowKey>> -> Frame<'TRowKey,'TColumnKey>
  new : rowIndex:IIndex<'TRowKey> * columnIndex:IIndex<'TColumnKey> * data:IVector<IVector> * indexBuilder:IIndexBuilder * vectorBuilder:IVectorBuilder -> Frame<'TRowKey,'TColumnKey>
  member AddColumn : column:'TColumnKey * series:ISeries<'TRowKey> -> unit
  member AddColumn : column:'TColumnKey * series:seq<'V> -> unit
  member AddColumn : column:'TColumnKey * series:ISeries<'TRowKey> * lookup:Lookup -> unit
  member AddColumn : column:'TColumnKey * series:seq<'V> * lookup:Lookup -> unit
  ...

Full name: Deedle.Frame<_,_>

--------------------
new : names:seq<'TColumnKey> * columns:seq<ISeries<'TRowKey>> -> Frame<'TRowKey,'TColumnKey>
new : rowIndex:Indices.IIndex<'TRowKey> * columnIndex:Indices.IIndex<'TColumnKey> * data:IVector<IVector> * indexBuilder:Indices.IIndexBuilder * vectorBuilder:Vectors.IVectorBuilder -> Frame<'TRowKey,'TColumnKey>
val expandAllCols : nesting:int -> frame:Frame<'R,string> -> Frame<'R,string> (requires equality)

Full name: Deedle.Frame.expandAllCols
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More information

Link:http://fssnip.net/m7
Posted:3 years ago
Author:Tomas Petricek
Tags: deedle , frame