GroupBy

Namespace: Polars.FSharp

Intermediate builder for eager GroupBy operations. Under the hood, this routes through the Lazy engine to maximize performance.

Constructors & Static Methods

new

new(df: DataFrame, groupByType: GroupByType, keys: Expr[]) : GroupBy

Parameters

Name	Type	Description
df	DataFrame	-
groupByType	GroupByType	-
keys	Expr[]	-

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Instance Methods

Agg

Aggregate columns using the provided expressions.

member Agg(aggs: seq<Expr>) : DataFrame
member Agg([<ParamArray>] aggs: Expr[]) : DataFrame

Parameters

Name	Type	Description
aggs	seq<Expr> / Expr[]	-

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All

Get all columns as lists.

member All : unit -> DataFrame

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Count

Count the number of rows in each group.

member Count : unit -> DataFrame

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First

Get the first value in each group.

member First(?ignoreNulls: bool) : DataFrame

Parameters

Name	Type	Description
ignoreNulls	bool (optional)	-

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Having

Filter groups with a predicate after aggregation.

member Having(predicate: Expr) : GroupBy

Parameters

Name	Type	Description
predicate	Expr	-

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Head

Get the first n rows of each group.

member Head(?n: int) : DataFrame

Parameters

Name	Type	Description
n	int (optional)	-

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Last

Get the last value in each group.

member Last(?ignoreNulls: bool) : DataFrame

Parameters

Name	Type	Description
ignoreNulls	bool (optional)	-

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Len

Get the length of each group.

member Len(?name: string) : DataFrame

Parameters

Name	Type	Description
name	string (optional)	-

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Max

Get the maximum value in each group.

member Max : unit -> DataFrame

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Mean

Get the mean value in each group.

member Mean : unit -> DataFrame

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Median

Get the median value in each group.

member Median : unit -> DataFrame

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Min

Get the minimum value in each group.

member Min : unit -> DataFrame

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NUnique

Count the number of unique values in each group.

member NUnique : unit -> DataFrame

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Quantile

Get the quantile value in each group.

member Quantile(quantile: float, ?interpolation: QuantileMethod) : DataFrame

Parameters

Name	Type	Description
quantile	float	-
interpolation	QuantileMethod (optional)	-

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Sum

Get the sum of values in each group.

member Sum : unit -> DataFrame

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Tail

Get the last n rows of each group.

member Tail(?n: int) : DataFrame

Parameters

Name	Type	Description
n	int (optional)	-

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