pl

Namespace: Polars.FSharp

The main entry point for Polars.NET F# API.

Contains factories for Expressions (pl.col, pl.lit), shortcuts for DataFrame operations, and types.

Properties & Indexers

Property	Type	Description
`boolean`	`DataType`	Boolean data type.
`date`	`DataType`	Date data type (no time).
`element`	`Expr`	Alias for an element being evaluated in an eval or filter expression.
`emptySchema`	`PolarsSchema`	Create an empty schema.
`float16`	`DataType`	16-bit Floating point data type.
`float32`	`DataType`	32-bit Floating point data type.
`float64`	`DataType`	64-bit Floating point data type.
`int128`	`DataType`	128-bit Integer data type.
`int16`	`DataType`	16-bit Integer data type.
`int32`	`DataType`	32-bit Integer data type.
`int64`	`DataType`	64-bit Integer data type.
`int8`	`DataType`	8-bit Integer data type.
`nullType`	`DataType`	Create a Null data type.
`sameAsInputType`	`DataType`	Create a SameAsInputType data type.
`string`	`DataType`	String data type (UTF-8).
`time`	`DataType`	Time data type (no date).
`uint16`	`DataType`	16-bit Unsigned Integer data type.
`uint32`	`DataType`	32-bit Unsigned Integer data type.
`uint64`	`DataType`	64-bit Unsigned Integer data type.
`uint8`	`DataType`	8-bit Unsigned Integer data type.
`unknownType`	`DataType`	Create an Unknown data type.(Same as SameAsInputType)
`utf8`	`DataType`	alias of String

Module Functions

pl.alias

Alias an expression with a new name.

fsharp

pl.alias : name: string -> expr: Expr -> Expr

Parameters

Name	Type	Description
`name`	`string`	-
`expr`	`Expr`	-

pl.alignDataFrames

Align a sequence of DataFrames on a common schema.

fsharp

pl.alignDataFrames : on: seq<Expr> -> how: JoinType -> select: seq<Expr> option -> descending: bool -> frames: seq<DataFrame> -> DataFrame[]

Parameters

Name	Type	Description
`on`	`seq<Expr>`	-
`how`	`JoinType`	-
`select`	`seq<Expr> option`	-
`descending`	`bool`	-
`frames`	`seq<DataFrame>`	-

pl.alignDataFramesAsync

Align a sequence of DataFrames on a common schema asynchronously.

fsharp

pl.alignDataFramesAsync : on: seq<Expr> -> how: JoinType -> select: seq<Expr> option -> descending: bool -> frames: seq<DataFrame> -> FSharpAsync<DataFrame[]>

Parameters

Name	Type	Description
`on`	`seq<Expr>`	-
`how`	`JoinType`	-
`select`	`seq<Expr> option`	-
`descending`	`bool`	-
`frames`	`seq<DataFrame>`	-

pl.alignLazyFrames

Align a sequence of frames using common values from one or more columns as a key.

fsharp

pl.alignLazyFrames : on: seq<Expr> -> how: JoinType -> select: seq<Expr> option -> descending: bool -> frames: seq<LazyFrame> -> LazyFrame[]

Parameters

Name	Type	Description
`on`	`seq<Expr>`	One or more columns whose unique values will be used to align the frames.
`how`	`JoinType`	Join strategy; defaults to outer join.
`select`	`seq<Expr> option`	Optional post-alignment column select.
`descending`	`bool`	Sort the alignment column values in descending order.
`frames`	`seq<LazyFrame>`	Sequence of DataFrames or LazyFrames.

pl.all

Select all columns. Equivalent to pl.col("*").

fsharp

pl.all : unit -> Expr

pl.allHorizontal

Compute the logical AND horizontally across columns.

Kleene logic is used to deal with nulls: if the column contains any null values and no True values, the output is null.

fsharp

pl.allHorizontal : exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	Column(s) to use in the aggregation.

pl.allOf

Evaluate a bitwise AND operation on the specified columns. This function is syntactic sugar for col(names).all().

fsharp

pl.allOf : names: seq<string> -> ignoreNulls: bool -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	The names of the columns to aggregate.
`ignoreNulls`	`bool`	If set to True (default), null values are ignored. If there are no non-null values, the output is False. If set to False, Kleene logic is used to deal with nulls: if the column contains any null values and no True values, the output is null.

Returns: A boolean aggregation expression.

pl.any

Evaluate a bitwise OR operation.

fsharp

pl.any : exprs: seq<string> -> ignoreNulls: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<string>`	Column(s) to use in aggregation.
`ignoreNulls`	`bool`	If set to True (default), null values are ignored. If there are no non-null values, the output is False. If set to False, Kleene logic is used to deal with nulls: if the column contains any null values and no True values, the output is null.

pl.anyHorizontal

Compute the logical OR horizontally across columns.

Kleene logic is used to deal with nulls: if the column contains any null values and no True values, the output is null.

fsharp

pl.anyHorizontal : exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	Column(s) to use in the aggregation. Accepts expression input. Strings are parsed as column names, other non-expression inputs are parsed as literals.

pl.arctan2

Compute two argument arctan in radians. Returns the angle (in radians) in the plane between the positive x-axis and the ray from the origin to (x,y).

fsharp

pl.arctan2 : y: Expr -> x: Expr -> Expr

Parameters

Name	Type	Description
`y`	`Expr`	-
`x`	`Expr`	-

pl.argSortBy

Return the row indices that would sort the column(s).

fsharp

pl.argSortBy : exprs: seq<Expr> -> descending: seq<bool> -> nullsLast: seq<bool> -> multithreaded: bool -> maintainOrder: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	-
`descending`	`seq<bool>`	Sort in descending order. When sorting by multiple columns, can be specified per column by passing a sequence of booleans.
`nullsLast`	`seq<bool>`	Place null values last.
`multithreaded`	`bool`	Sort using multiple threads.
`maintainOrder`	`bool`	Whether the order should be maintained if elements are equal.

pl.argWhere

Return indices where condition evaluates True.

fsharp

pl.argWhere : condition: Expr -> Expr

Parameters

Name	Type	Description
`condition`	`Expr`	Boolean expression/Series to evaluate

pl.argWhereAsSeries

Return indices where condition evaluates True and return the result as a Series.

fsharp

pl.argWhereAsSeries : condition: Expr -> Series

Parameters

Name	Type	Description
`condition`	`Expr`	Boolean expression/Series to evaluate

pl.array

Array data type.(Also known as fixed length list)

fsharp

pl.array : inner: DataType -> shape: uint32[] -> DataType

Parameters

Name	Type	Description
`inner`	`DataType`	-
`shape`	`uint32[]`	-

pl.asLazy

fsharp

pl.asLazy : df: DataFrame -> LazyFrame

Parameters

Name	Type	Description
`df`	`DataFrame`	-

pl.asStruct

Create a Struct expression from a list of expressions.

fsharp

pl.asStruct : exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	-

pl.businessDayCount

Count the number of business days between start and end (not including end).

fsharp

pl.businessDayCount : start: Expr -> endDay: Expr -> weekMask: seq<bool> -> holidays: Series option -> Expr

Parameters

Name	Type	Description
`start`	`Expr`	Start dates.
`endDay`	`Expr`	End dates.
`weekMask`	`seq<bool>`	Which days of the week to count. The default is Monday to Friday. If you wanted to count only Monday to Thursday, you would pass (True, True, True, True, False, False, False).
`holidays`	`Series option`	Holidays to exclude from the count.

pl.categorical

Create a Categorical data type with the given categories.

fsharp

pl.categorical : categories: Categories option -> DataType

Parameters

Name	Type	Description
`categories`	`Categories option`	The categories.

pl.categories

Create a Categories object with the given name, name space, and physical type.

fsharp

pl.categories : name: string option -> nameSpace: string option -> physical: CategoricalPhysical option -> Categories

Parameters

Name	Type	Description
`name`	`string option`	The category name.
`nameSpace`	`string option`	The category name space.
`physical`	`CategoricalPhysical option`	The physical type.

pl.coalesce

(Lazy) Evaluates the arguments in order and returns the first non-null value.

fsharp

pl.coalesce : exprs: seq<'a> -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<'a>`	Expressions to evaluate. Strings, Literals, Series are automatically converted.

Returns: A new expression.

pl.coalesceAsSeries

(Eager) Evaluates the arguments eagerly and returns the first non-null value as a Series.

fsharp

pl.coalesceAsSeries : exprs: seq<'a> -> Series

Parameters

Name	Type	Description
`exprs`	`seq<'a>`	Expressions or Series to evaluate.

pl.col

Create an expression representing a column with the given name.

fsharp

pl.col : name: string -> Expr

Parameters

Name	Type	Description
`name`	`string`	The name of the column.

pl.collect

Collect LazyFrame into DataFrame (Eager execution).

fsharp

pl.collect : lf: LazyFrame -> DataFrame

Parameters

Name	Type	Description
`lf`	`LazyFrame`	-

pl.collectAll

Collect multiple LazyFrames concurrently.

fsharp

pl.collectAll : engine: Engine -> frames: seq<LazyFrame> -> DataFrame[]

Parameters

Name	Type	Description
`engine`	`Engine`	-
`frames`	`seq<LazyFrame>`	-

pl.collectAllAsync

Collect multiple LazyFrames concurrently and asynchronously.

fsharp

pl.collectAllAsync : engine: Engine -> frames: seq<LazyFrame> -> FSharpAsync<DataFrame[]>

Parameters

Name	Type	Description
`engine`	`Engine`	-
`frames`	`seq<LazyFrame>`	-

pl.collectWithEngine

fsharp

pl.collectWithEngine : engine: Engine -> lf: LazyFrame -> DataFrame

Parameters

Name	Type	Description
`engine`	`Engine`	-
`lf`	`LazyFrame`	-

pl.cols

Create an expression representing multiple columns (Wildcard).

fsharp

pl.cols : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	-

Example

fsharp

pl.cols ["A"; "B"]

pl.combineDateAndTime

Combine a Date expression and a Time expression into a Datetime expression. Usage: pl.col("date") |> pl.combineDateAndTime (pl.col("time"))

fsharp

pl.combineDateAndTime : time: Expr -> date: Expr -> Expr

Parameters

Name	Type	Description
`time`	`Expr`	-
`date`	`Expr`	-

pl.combineDateAndTimeUnit

Combine a Date expression and a Time expression with a specific TimeUnit. Usage: pl.col("date") |> pl.combineDateAndTimeUnit (pl.col("time")) TimeUnit.Milliseconds

fsharp

pl.combineDateAndTimeUnit : time: Expr -> tu: TimeUnit -> date: Expr -> Expr

Parameters

Name	Type	Description
`time`	`Expr`	-
`tu`	`TimeUnit`	-
`date`	`Expr`	-

pl.concatArray

Combine multiple expressions horizontally into an array element.

fsharp

pl.concatArray : columns: seq<'a> -> Expr

Parameters

Name	Type	Description
`columns`	`seq<'a>`	-

pl.concatDataFrame

Concat DataFrames

fsharp

pl.concatDataFrame : how: ConcatType -> dfs: seq<DataFrame> -> DataFrame

Parameters

Name	Type	Description
`how`	`ConcatType`	-
`dfs`	`seq<DataFrame>`	-

pl.concatExpr

Concat multiple expressions into a single expression.

fsharp

pl.concatExpr : exprs: seq<'a> -> rechunk: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<'a>`	-
`rechunk`	`bool`	-

pl.concatLazyFrame

Concat LazyFrames

fsharp

pl.concatLazyFrame : how: ConcatType -> lfs: seq<LazyFrame> -> LazyFrame

Parameters

Name	Type	Description
`how`	`ConcatType`	-
`lfs`	`seq<LazyFrame>`	-

pl.concatList

Combine multiple expressions horizontally into a List element. Supports Selectors (e.g. pl.concatList([pl.cs.numeric()])).

fsharp

pl.concatList : columns: seq<'a> -> Expr

Parameters

Name	Type	Description
`columns`	`seq<'a>`	-

pl.concatSeries

Concatenates a sequence of Series into a single Series. Preserves caller immutability by creating a cloned accumulator.

fsharp

pl.concatSeries : series: seq<Series> -> Series

Parameters

Name	Type	Description
`series`	`seq<Series>`	-

pl.concatString

Horizontally concatenate columns into a single string column.

fsharp

pl.concatString : exprs: seq<'a> -> separator: string -> ignoreNulls: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<'a>`	Columns to concatenate into a single string column.
`separator`	`string`	String that will be used to separate the values of each column.
`ignoreNulls`	`bool`	Ignore null values. If set to False, null values will be propagated. if the row contains any null values, the output is null.

pl.corrPearson

Compute the Pearson’s correlation between two columns.

fsharp

pl.corrPearson : a: Expr -> b: Expr -> Expr

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.

pl.corrPearsonAsSeries

Compute the Pearson’s correlation between two columns and return the result as a Series.

fsharp

pl.corrPearsonAsSeries : a: Expr -> b: Expr -> Series

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.

pl.corrSpearman

Compute the Spearman rank correlation between two columns.

fsharp

pl.corrSpearman : a: Expr -> b: Expr -> propagateNans: bool -> Expr

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`propagateNans`	`bool`	Propagate NaNs.

pl.corrSpearmanAsSeries

Compute the Spearman rank correlation between two columns and return the result as a Series.

fsharp

pl.corrSpearmanAsSeries : a: Expr -> b: Expr -> propagateNans: bool -> Series

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`propagateNans`	`bool`	Propagate NaNs.

pl.count

Return the number of non-null values in the column.

fsharp

pl.count : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	-

pl.cov

Compute the covariance between two columns/ expressions.

fsharp

pl.cov : a: Expr -> b: Expr -> ddof: byte -> Expr

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`ddof`	`byte`	“Delta Degrees of Freedom”: the divisor used in the calculation is N - ddof, where N represents the number of elements. By default ddof is 1.

pl.covAsSeries

Compute the covariance of two expressions and return the result as a Series.

fsharp

pl.covAsSeries : a: Expr -> b: Expr -> ddof: byte -> Series

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`ddof`	`byte`	“Delta Degrees of Freedom”: the divisor used in the calculation is N - ddof, where N represents the number of elements. By default ddof is 1.

pl.cumCount

Return the cumulative count of the non-null values in the column.This function is syntactic sugar for Col(column).CumCount().

fsharp

pl.cumCount : column: string -> Expr

Parameters

Name	Type	Description
`column`	`string`	Name of the columns to use.

pl.cumSum

Cumulatively sum all values. Syntactic sugar for Col(names).CumSum().

fsharp

pl.cumSum : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	-

pl.dataTypeOf

Gets the DataType of an expression. Equivalent to Python's polars.dtype_of()

fsharp

pl.dataTypeOf : expr: Expr -> DataTypeExpr

Parameters

Name	Type	Description
`expr`	`Expr`	-

pl.dataframe

Create a DataFrame from a sequence of Series.

fsharp

pl.dataframe : series: seq<Series> -> DataFrame

Parameters

Name	Type	Description
`series`	`seq<Series>`	-

pl.dateRange

Generate a date range.

fsharp

pl.dateRange : start: DateOnly -> endRange: DateOnly -> interval: Dur -> closed: ClosedInterval -> Expr

Parameters

Name	Type	Description
`start`	`DateOnly`	Lower bound of the date range.
`endRange`	`DateOnly`	Upper bound of the date range.
`interval`	`Dur`	Interval of the range periods, “1w2d” # 1 week, 2 days.Default is 1 day.
`closed`	`ClosedInterval`	Define which sides of the range are closed

Returns: Column of data type Date

pl.dateRangeAsSeries

Generate a date range as a Series.

fsharp

pl.dateRangeAsSeries : name: string -> start: DateOnly -> endRange: DateOnly -> interval: Dur -> closed: ClosedInterval -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the series.
`start`	`DateOnly`	Lower bound of the date range.
`endRange`	`DateOnly`	Upper bound of the date range.
`interval`	`Dur`	Interval of the range periods, “1w2d” # 1 week, 2 days.Default is 1 day.
`closed`	`ClosedInterval`	Define which sides of the range are closed

Returns: Column of data type Date

pl.dateRanges

Create a column of date ranges. DataType will be a list of dates

fsharp

pl.dateRanges : start: DateOnly -> endRange: DateOnly -> interval: Dur -> closed: ClosedInterval -> Expr

Parameters

Name	Type	Description
`start`	`DateOnly`	Lower bound of the date range.
`endRange`	`DateOnly`	Upper bound of the date range.
`interval`	`Dur`	Interval of the range periods, “1w2d” # 1 week, 2 days.Default is 1 day.
`closed`	`ClosedInterval`	Define which sides of the range are closed

Returns: Column of data type Date

pl.dateRangesAsSeries

Generate a date range as a Series.

fsharp

pl.dateRangesAsSeries : name: string -> start: DateOnly -> endRange: DateOnly -> interval: Dur -> closed: ClosedInterval -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the series.
`start`	`DateOnly`	Lower bound of the date range.
`endRange`	`DateOnly`	Upper bound of the date range.
`interval`	`Dur`	Interval of the range periods, “1w2d” # 1 week, 2 days.Default is 1 day.
`closed`	`ClosedInterval`	Define which sides of the range are closed

Returns: Column of data type Date

pl.datetime

Datetime data type.

fsharp

pl.datetime : unit: TimeUnit -> timeZone: string option -> DataType

Parameters

Name	Type	Description
`unit`	`TimeUnit`	-
`timeZone`	`string option`	-

pl.datetimeRange

Generate a datetime range.

fsharp

pl.datetimeRange : start: DateTime -> endRange: DateTime -> interval: Dur -> closed: ClosedInterval -> unit: TimeUnit -> timeZone: string option -> Expr

Parameters

Name	Type	Description
`start`	`DateTime`	Lower bound of the datetime range.
`endRange`	`DateTime`	Upper bound of the datetime range.
`interval`	`Dur`	Interval of the range periods
`closed`	`ClosedInterval`	Define which sides of the range are closed
`unit`	`TimeUnit`	Time unit of the resulting Datetime data type.
`timeZone`	`string option`	Time zone of the resulting Datetime data type.

pl.datetimeRangeAsSeries

Converts a datetime range expression to a Series with the specified name.

fsharp

pl.datetimeRangeAsSeries : name: string -> start: DateTime -> endRange: DateTime -> interval: Dur -> closed: ClosedInterval -> unit: TimeUnit -> timeZone: string option -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the resulting Series.
`start`	`DateTime`	Start datetime of the range.
`endRange`	`DateTime`	End datetime of the range.
`interval`	`Dur`	Interval between datetime values.
`closed`	`ClosedInterval`	Closed window of the range.
`unit`	`TimeUnit`	Time unit of the resulting Datetime data type.
`timeZone`	`string option`	Time zone of the resulting Datetime data type.

pl.datetimeRanges

Creates a datetime range expression from the specified start, end, interval, closed window, unit, and time zone.

fsharp

pl.datetimeRanges : start: DateTime -> endRange: DateTime -> interval: Dur -> closed: ClosedInterval -> unit: TimeUnit -> timeZone: string option -> Expr

Parameters

Name	Type	Description
`start`	`DateTime`	-
`endRange`	`DateTime`	-
`interval`	`Dur`	-
`closed`	`ClosedInterval`	-
`unit`	`TimeUnit`	-
`timeZone`	`string option`	-

pl.datetimeRangesAsSeries

Converts a datetime range expression to a Series with the specified name.

fsharp

pl.datetimeRangesAsSeries : name: string -> start: DateTime -> endRange: DateTime -> interval: Dur -> closed: ClosedInterval -> unit: TimeUnit -> timeZone: string option -> Series

Parameters

Name	Type	Description
`name`	`string`	-
`start`	`DateTime`	-
`endRange`	`DateTime`	-
`interval`	`Dur`	-
`closed`	`ClosedInterval`	-
`unit`	`TimeUnit`	-
`timeZone`	`string option`	-

pl.decimal

Decimal data type.

fsharp

pl.decimal : precision: int -> scale: int -> DataType

Parameters

Name	Type	Description
`precision`	`int`	-
`scale`	`int`	-

pl.duration

Duration (TimeSpan) data type.

fsharp

pl.duration : unit: TimeUnit -> DataType

Parameters

Name	Type	Description
`unit`	`TimeUnit`	-

pl.enumType

Create an Enum data type with the given categories.

fsharp

pl.enumType : categories: Categories -> DataType

Parameters

Name	Type	Description
`categories`	`Categories`	The categories.

pl.escapeRegex

Escapes string regex meta characters.

fsharp

pl.escapeRegex : s: string -> string

Parameters

Name	Type	Description
`s`	`string`	The string to escape.

Returns: A string with regex meta characters escaped.

pl.excludeCols

Represent all columns except for the given columns. Syntactic sugar for pl.all().Exclude(columns).

fsharp

pl.excludeCols : columns: seq<string> -> Expr

Parameters

Name	Type	Description
`columns`	`seq<string>`	-

pl.excludeDataTypes

Represent all columns except for the given datatypes. Syntactic sugar for pl.all().Exclude(dtypes).

fsharp

pl.excludeDataTypes : dtypes: seq<DataType> -> Expr

Parameters

Name	Type	Description
`dtypes`	`seq<DataType>`	-

pl.explainAll

Explain multiple LazyFrames as if passed to collect_all. Common Subplan Elimination is applied on the combined plan, meaning that diverging queries will run only once.

fsharp

pl.explainAll : lazyFrames: seq<LazyFrame> -> string

Parameters

Name	Type	Description
`lazyFrames`	`seq<LazyFrame>`	A list of LazyFrames to collect.

Returns: Explained plan.

pl.extensionType

Create an Extension data type

fsharp

pl.extensionType : name: string -> inner: DataType -> metadata: string option -> DataType

Parameters

Name	Type	Description
`name`	`string`	The registered name of the extension type (e.g. "geoarrow.wkb")
`inner`	`DataType`	The physical storage data type
`metadata`	`string option`	Optional metadata string

pl.field

Create a Struct Field with the given name and data type.

fsharp

pl.field : name: string -> dtype: DataType -> Field

Parameters

Name	Type	Description
`name`	`string`	The field name.
`dtype`	`DataType`	The data type.

pl.firstCol

Get the first column.

fsharp

pl.firstCol : unit -> Selector

pl.firstValue

Get the first value of the group/series.

fsharp

pl.firstValue : columns: seq<string> -> (unit -> Expr)

Parameters

Name	Type	Description
`columns`	`seq<string>`	-

Returns: A new expression representing the first value.

pl.fold

Accumulate over multiple columns horizontally/row-wise.

fsharp

pl.fold : f: (Expr -> (Expr -> Expr)) -> acc: Expr -> exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`f`	`(Expr -> (Expr -> Expr))`	-
`acc`	`Expr`	-
`exprs`	`seq<Expr>`	-

pl.format

Format expressions as a string.

fsharp

pl.format : format: string -> exprs: seq<'a> -> Expr

Parameters

Name	Type	Description
`format`	`string`	-
`exprs`	`seq<'a>`	-

pl.fromEpoch

Parses an integer column (seconds, milliseconds, etc.) into a Datetime or Date expression.

fsharp

pl.fromEpoch : column: Expr -> timeUnit: EpochTimeUnit -> Expr

Parameters

Name	Type	Description
`column`	`Expr`	-
`timeUnit`	`EpochTimeUnit`	-

pl.ifElse

Create an if-else expression.

fsharp

pl.ifElse : predicate: Expr -> ifTrue: Expr -> ifFalse: Expr -> Expr

Parameters

Name	Type	Description
`predicate`	`Expr`	-
`ifTrue`	`Expr`	-
`ifFalse`	`Expr`	-

pl.implode

Aggregate all column values into a list. This function is syntactic sugar for pl.col(name).Implode().

fsharp

pl.implode : column: string -> Expr

Parameters

Name	Type	Description
`column`	`string`	Column name

pl.intRange

Generate a range of integers as an Expression.

fsharp

pl.intRange : start: int64 -> endRange: int64 -> step: int64 -> Expr

Parameters

Name	Type	Description
`start`	`int64`	Start of the range (inclusive).
`endRange`	`int64`	End of the range (exclusive).
`step`	`int64`	Step size of the range.

Returns: A Literal Expression containing the integer series.

pl.intRangeAsSeries

Generate a range of integers as a Series.

fsharp

pl.intRangeAsSeries : name: string -> start: int64 -> endRange: int64 -> step: int64 -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the series.
`start`	`int64`	Start of the range (inclusive).
`endRange`	`int64`	End of the range (exclusive).
`step`	`int64`	Step size of the range.

Returns: A Series containing the integer series.

pl.intRanges

Generate a range of integers for each row of the input columns. Resulting column is of dtype List(dtype).

fsharp

pl.intRanges : start: int64 -> endRange: int64 -> step: int64 -> Expr

Parameters

Name	Type	Description
`start`	`int64`	-
`endRange`	`int64`	-
`step`	`int64`	-

pl.intRangesAsSeries

fsharp

pl.intRangesAsSeries : name: string -> start: int64 -> endRange: int64 -> step: int64 -> Series

Parameters

Name	Type	Description
`name`	`string`	-
`start`	`int64`	-
`endRange`	`int64`	-
`step`	`int64`	-

pl.lastCol

Get the last column.

fsharp

pl.lastCol : unit -> Selector

pl.lastValue

Get the last value of the group/series.

fsharp

pl.lastValue : columns: seq<string> -> (unit -> Expr)

Parameters

Name	Type	Description
`columns`	`seq<string>`	-

Returns: A new expression representing the first value.

pl.len

Return the lines count of current context.

fsharp

pl.len : unit -> Expr

pl.linearSpace

Generate a series of equally-spaced points.

fsharp

pl.linearSpace : start: Expr -> endRange: Expr -> numSamples: int -> closed: ClosedInterval -> Expr

Parameters

Name	Type	Description
`start`	`Expr`	Lower bound of the linear space.
`endRange`	`Expr`	Upper bound of the linear space.
`numSamples`	`int`	Number of samples to generate.
`closed`	`ClosedInterval`	Whether the intervals are closed or open.

pl.linearSpaceAsSeries

Converts a linear space expression to a Series with the specified name.

fsharp

pl.linearSpaceAsSeries : name: string -> start: Expr -> endRange: Expr -> numSamples: int -> closed: ClosedInterval -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the resulting Series.
`start`	`Expr`	Lower bound of the linear space.
`endRange`	`Expr`	Upper bound of the linear space.
`numSamples`	`int`	Number of samples to generate.
`closed`	`ClosedInterval`	Whether the intervals are closed or open.

pl.linearSpaces

Create a column of linearly-spaced sequences for each row.

fsharp

pl.linearSpaces : start: Expr -> endRange: Expr -> numSamples: int -> closed: ClosedInterval -> asArray: bool -> Expr

Parameters

Name	Type	Description
`start`	`Expr`	Lower bound.
`endRange`	`Expr`	Upper bound.
`numSamples`	`int`	Number of samples.
`closed`	`ClosedInterval`	Whether the intervals are closed or open.
`asArray`	`bool`	If true, returns an Array dtype instead of List. Requires numSamples to be a constant.

pl.linearSpacesAsSeries

Converts a linear spaces expression to a Series with the specified name.

fsharp

pl.linearSpacesAsSeries : name: string -> start: Expr -> endRange: Expr -> numSamples: int -> closed: ClosedInterval -> asArray: bool -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the resulting Series.
`start`	`Expr`	Lower bound.
`endRange`	`Expr`	Upper bound.
`numSamples`	`int`	Number of samples.
`closed`	`ClosedInterval`	Whether the intervals are closed or open.
`asArray`	`bool`	If true, returns an Array dtype instead of List. Requires numSamples to be a constant.

pl.list

List data type.

fsharp

pl.list : inner: DataType -> DataType

Parameters

Name	Type	Description
`inner`	`DataType`	-

pl.lit

Create a literal expression from a value.

fsharp

pl.lit : value: 'T -> Expr

Parameters

Name	Type	Description
`value`	`'T`	-

Example

fsharp

df.Filter(pl.col("Age") .> pl.lit(18))

pl.lit$W

fsharp

pl.lit$W : op_Dollar: (LitMechanism -> ('T -> Expr)) -> value: 'T -> Expr

Parameters

Name	Type	Description
`op_Dollar`	`(LitMechanism -> ('T -> Expr))`	-
`value`	`'T`	-

pl.litBinary

Creates a scalar Binary Literal Expression from a byte array.

fsharp

pl.litBinary : value: byte[] -> Expr

Parameters

Name	Type	Description
`value`	`byte[]`	-

pl.litNull

Create a literal expression for null value.

fsharp

pl.litNull : unit -> Expr

pl.litSeries

Create a literal expression from a Series.

fsharp

pl.litSeries : series: Series -> Expr

Parameters

Name	Type	Description
`series`	`Series`	-

pl.litStruct

Create a Struct Expression from a single anonymous record or class instance.

Example: pl.litStruct {| A = 1; B = "hi" |}

fsharp

pl.litStruct : value: 'T -> Expr

Parameters

Name	Type	Description
`value`	`'T`	The object to pack into a struct.

pl.litStructs

Create a Struct Expression from a sequence of objects.

The properties of the objects become the fields of the struct.

fsharp

pl.litStructs : values: seq<'T> -> Expr

Parameters

Name	Type	Description
`values`	`seq<'T>`	The sequence of objects to pack.

pl.max

Get the maximum value. Syntactic sugar for Col(names).Max().

fsharp

pl.max : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	Name(s) of the columns to use in the aggregation.

pl.maxHorizontal

Get the maximum value horizontally across columns.

fsharp

pl.maxHorizontal : exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	Column(s) to use in the aggregation.

pl.mean

Get the Mean value. Syntactic sugar for Col(names).Mean().

fsharp

pl.mean : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	Name(s) of the columns to use in the aggregation.

pl.meanHorizontal

Compute the mean of all values horizontally across columns.

fsharp

pl.meanHorizontal : exprs: seq<Expr> -> ignoreNulls: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	Column(s) to use in the aggregation. Accepts expression input. Strings are parsed as column names, other non-expression inputs are parsed as literals.
`ignoreNulls`	`bool`	Ignore null values (default). If set to False, any null value in the input will lead to a null output.

pl.median

Get the median value.This function is syntactic sugar for Pl.Col(columns).Median().

fsharp

pl.median : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	One or more column names.

pl.nUnique

Count unique values.This function is syntactic sugar for pl.col(columns).NUnique().

fsharp

pl.nUnique : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	-

pl.nth

Get the nth column(s) of the context.

fsharp

pl.nth : indices: seq<int64> -> Selector

Parameters

Name	Type	Description
`indices`	`seq<int64>`	One or more indices representing the columns to retrieve.

pl.ones

Construct a column of length n filled with ones. This is syntactic sugar for the repeat function.

fsharp

pl.ones : n: int -> Expr

Parameters

Name	Type	Description
`n`	`int`	Length of the resulting column.

pl.onesAsSeries

fsharp

pl.onesAsSeries : n: int -> Series

Parameters

Name	Type	Description
`n`	`int`	-

pl.otherwise

Terminal operator that provides the default fallback expression for a when-then-otherwise chain.

fsharp

pl.otherwise : fallback: Expr -> thenBlock: ThenBranch -> Expr

Parameters

Name	Type	Description
`fallback`	`Expr`	The fallback expression.
`thenBlock`	`ThenBranch`	The ThenBranch collector block.

Returns: The compiled ternary expression tree.

pl.quantile

Syntactic sugar for pl.Col("foo").Quantile(..).

fsharp

pl.quantile : column: string -> quantile: float -> interpolation: QuantileMethod -> Expr

Parameters

Name	Type	Description
`column`	`string`	Column name.
`quantile`	`float`	Quantile between 0.0 and 1.0.
`interpolation`	`QuantileMethod`	Interpolation method.

pl.reduce

Reduce multiple columns horizontally/row-wise.

fsharp

pl.reduce : f: (Expr -> (Expr -> Expr)) -> exprs: seq<Expr> -> Expr

Parameters

Name	Type	Description
`f`	`(Expr -> (Expr -> Expr))`	-
`exprs`	`seq<Expr>`	-

pl.registerExtensionAsStorage

fsharp

pl.registerExtensionAsStorage : extName: string -> unit

Parameters

Name	Type	Description
`extName`	`string`	The registered name.

pl.registerExtensionType

fsharp

pl.registerExtensionType : extName: string -> factory: ((DataType * string option) -> DataType) -> unit

Parameters

Name	Type	Description
`extName`	`string`	The registered name.
`factory`	`((DataType * string option) -> DataType)`	The factory function deserialize the extension type.

pl.repeat

Construct a column of length n filled with the given value.

fsharp

pl.repeat : value: Expr -> n: int -> dtype: DataType option -> Expr

Parameters

Name	Type	Description
`value`	`Expr`	Value to repeat.
`n`	`int`	Length of the resulting column.
`dtype`	`DataType option`	Data type of the resulting column. If set to None (default), data type is inferred from the given value. Defaults to Int32 for integer values, unless Int64 is required to fit the given value. Defaults to Float64 for float values.

pl.repeatAsSeries

fsharp

pl.repeatAsSeries : value: Expr -> n: int -> dtype: DataType option -> Series

Parameters

Name	Type	Description
`value`	`Expr`	-
`n`	`int`	-
`dtype`	`DataType option`	-

pl.rollingCorr

Compute the rolling correlation between two columns/ expressions. The window at a given row includes the row itself and the window_size - 1 elements before it.

fsharp

pl.rollingCorr : a: Expr -> b: Expr -> windowSize: uint32 -> minSamples: uint32 option -> Expr

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`windowSize`	`uint32`	The length of the window.
`minSamples`	`uint32 option`	The number of values in the window that should be non-null before computing a result. If None, it will be set equal to window size.

pl.rollingCov

Compute the rolling covariance between two columns/ expressions. The window at a given row includes the row itself and the window_size - 1 elements before it.

fsharp

pl.rollingCov : a: Expr -> b: Expr -> windowSize: uint32 -> minSamples: uint32 option -> ddof: byte -> Expr

Parameters

Name	Type	Description
`a`	`Expr`	Column name or Expression.
`b`	`Expr`	Column name or Expression.
`windowSize`	`uint32`	The length of the window.
`minSamples`	`uint32 option`	The number of values in the window that should be non-null before computing a result. If None, it will be set equal to window size.
`ddof`	`byte`	Delta degrees of freedom. The divisor used in calculations is N - ddof, where N represents the number of elements.

pl.schema

Create a schema from a sequence of fields.

fsharp

pl.schema : fields: seq<Field> -> PolarsSchema

Parameters

Name	Type	Description
`fields`	`seq<Field>`	-

pl.selectExprsEager

Run polars expressions without a context. This is syntactic sugar for running df.select on an empty DataFrame.

fsharp

pl.selectExprsEager : exprs: seq<Expr> -> DataFrame

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	-

pl.selectExprsLazy

Run polars expressions without a context. This is syntactic sugar for running lf.select on an empty LazyFrame.

fsharp

pl.selectExprsLazy : exprs: seq<Expr> -> LazyFrame

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	-

pl.selfDataType

Represents the intrinsic data type of the current element. Equivalent to Python's polars.self_dtype()

fsharp

pl.selfDataType : unit -> DataTypeExpr

pl.series

Create a Series from a sequence of values.

fsharp

pl.series : name: string -> data: seq<'T> -> Series

Parameters

Name	Type	Description
`name`	`string`	-
`data`	`seq<'T>`	-

pl.setEnvVar

Set environment variable.

fsharp

pl.setEnvVar : key: string -> value: string -> unit

Parameters

Name	Type	Description
`key`	`string`	-
`value`	`string`	-

pl.sqlContext

Create a SQL context for executing SQL queries on LazyFrames.

fsharp

pl.sqlContext : unit -> SqlContext

pl.sqlExpr

Create a Polars Expr from a SQL string.

fsharp

pl.sqlExpr : sql: string -> Expr

Parameters

Name	Type	Description
`sql`	`string`	The SQL expression string.

Returns: A Polars Expr representing the SQL logic.

pl.sqlExprs

Create an array of Polars Exprs from a collection of SQL strings.

fsharp

pl.sqlExprs : sqls: seq<string> -> Expr[]

Parameters

Name	Type	Description
`sqls`	`seq<string>`	The collection of SQL expression strings.

Returns: An array of Polars Expr objects.

pl.std

Get the standard deviation. This function is syntactic sugar for pl.col(column).Std(ddof).

fsharp

pl.std : column: string -> ddof: byte -> Expr

Parameters

Name	Type	Description
`column`	`string`	Column name.
`ddof`	`byte`	“Delta Degrees of Freedom”: the divisor used in the calculation is N - ddof, where N represents the number of elements. By default ddof is 1.

pl.structSeries

Collect several expressions and combine them into a single Struct Series

fsharp

pl.structSeries : exprs: seq<Expr> -> Series

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	-

pl.structType

Struct data type.

fsharp

pl.structType : fields: seq<Field> -> DataType

Parameters

Name	Type	Description
`fields`	`seq<Field>`	-

pl.sum

Get the Sum value. Syntactic sugar for Col(names).Sum().

fsharp

pl.sum : names: seq<string> -> Expr

Parameters

Name	Type	Description
`names`	`seq<string>`	Name(s) of the columns to use in the aggregation.

pl.sumHorizontal

Sum all values horizontally across columns.

fsharp

pl.sumHorizontal : exprs: seq<Expr> -> ignoreNulls: bool -> Expr

Parameters

Name	Type	Description
`exprs`	`seq<Expr>`	An iterable of expressions
`ignoreNulls`	`bool`	Whether to ignore null values

pl.then'

Connects a statement expression to the preceding when' condition.

fsharp

pl.then' : statement: Expr -> whenBlock: WhenCondition -> ThenBranch

Parameters

Name	Type	Description
`statement`	`Expr`	The expression to evaluate if the condition is true.
`whenBlock`	`WhenCondition`	The WhenCondition block built by pl.when'.

Returns: A new ThenBranch collector block.

pl.threadPoolSize

Get thread pool size.

fsharp

pl.threadPoolSize : unit -> int

pl.timeRange

Generate a time range.

fsharp

pl.timeRange : start: TimeOnly -> endRange: TimeOnly -> interval: Dur -> closed: ClosedInterval -> Expr

Parameters

Name	Type	Description
`start`	`TimeOnly`	Lower bound of the time range. If omitted, defaults to TimeOnly.MinValue
`endRange`	`TimeOnly`	-
`interval`	`Dur`	Interval of the range periods
`closed`	`ClosedInterval`	Define which sides of the range are closed.

pl.timeRangeAsSeries

Converts a time range expression to a Series with the specified name.

fsharp

pl.timeRangeAsSeries : name: string -> start: TimeOnly -> endRange: TimeOnly -> interval: Dur -> closed: ClosedInterval -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the resulting Series.
`start`	`TimeOnly`	Start time of the range.
`endRange`	`TimeOnly`	End time of the range.
`interval`	`Dur`	Interval between time values.
`closed`	`ClosedInterval`	Closed window of the range.

pl.timeRanges

Creates a time range expression from the specified start, end, interval, and closed window.

fsharp

pl.timeRanges : start: TimeOnly -> endRange: TimeOnly -> interval: Dur -> closed: ClosedInterval -> Expr

Parameters

Name	Type	Description
`start`	`TimeOnly`	Start time of the range.
`endRange`	`TimeOnly`	End time of the range.
`interval`	`Dur`	Interval between time values.
`closed`	`ClosedInterval`	Closed window of the range.

pl.timeRangesAsSeries

Converts a time range expression to a Series with the specified name.

fsharp

pl.timeRangesAsSeries : name: string -> start: TimeOnly -> endRange: TimeOnly -> interval: Dur -> closed: ClosedInterval -> Series

Parameters

Name	Type	Description
`name`	`string`	Name of the resulting Series.
`start`	`TimeOnly`	Start time of the range.
`endRange`	`TimeOnly`	End time of the range.
`interval`	`Dur`	Interval between time values.
`closed`	`ClosedInterval`	Closed window of the range.

pl.tryGetExtensionType

Get the extension type registration info for the given extension name.

fsharp

pl.tryGetExtensionType : extName: string -> ExtensionRegistration option

Parameters

Name	Type	Description
`extName`	`string`	The registered name.

pl.unregisterExtensionType

Unregister the extension type for the given extension name.

fsharp

pl.unregisterExtensionType : extName: string -> unit

Parameters

Name	Type	Description
`extName`	`string`	The registered name.

pl.var

Get the variance. This function is syntactic sugar for Pl.Col(column).Var(ddof).

fsharp

pl.var : column: string -> ddof: byte -> Expr

Parameters

Name	Type	Description
`column`	`string`	Column name.
`ddof`	`byte`	“Delta Degrees of Freedom”: the divisor used in the calculation is N - ddof, where N represents the number of elements. By default ddof is 1.

pl.when'

Starts a conditional when-then-otherwise expression branch natively in F#.

fsharp

pl.when' : condition: Expr -> WhenCondition

Parameters

Name	Type	Description
`condition`	`Expr`	The initial filter condition expression.

Returns: An intermediate WhenCondition state object.

pl.zeros

Construct a column of length n filled with zeros. This is syntactic sugar for the repeat function.

fsharp

pl.zeros : n: int -> Expr

Parameters

Name	Type	Description
`n`	`int`	Length of the resulting column.

pl.zerosAsSeries

fsharp

pl.zerosAsSeries : n: int -> Series

Parameters

Name	Type	Description
`n`	`int`	-

pl ​

Properties & Indexers ​

Module Functions ​

pl.alias ​

pl.alignDataFrames ​

pl.alignDataFramesAsync ​

pl.alignLazyFrames ​

pl.all ​

pl.allHorizontal ​

pl.allOf ​

pl.any ​

pl.anyHorizontal ​

pl.arctan2 ​

pl.argSortBy ​

pl.argWhere ​

pl.argWhereAsSeries ​

pl.array ​

pl.asLazy ​

pl.asStruct ​

pl.businessDayCount ​

pl.categorical ​

pl.categories ​

pl.coalesce ​

pl.coalesceAsSeries ​

pl.col ​

pl.collect ​

pl.collectAll ​

pl.collectAllAsync ​

pl.collectWithEngine ​

pl.cols ​

pl.combineDateAndTime ​

pl.combineDateAndTimeUnit ​

pl.concatArray ​

pl.concatDataFrame ​

pl.concatExpr ​

pl.concatLazyFrame ​

pl.concatList ​

pl.concatSeries ​

pl.concatString ​

pl.corrPearson ​

pl.corrPearsonAsSeries ​

pl.corrSpearman ​

pl.corrSpearmanAsSeries ​

pl.count ​

pl.cov ​

pl.covAsSeries ​

pl.cumCount ​

pl.cumSum ​

pl.dataTypeOf ​

pl.dataframe ​

pl.dateRange ​

pl.dateRangeAsSeries ​

pl.dateRanges ​

pl.dateRangesAsSeries ​

pl.datetime ​

pl.datetimeRange ​

pl.datetimeRangeAsSeries ​

pl.datetimeRanges ​

pl.datetimeRangesAsSeries ​

pl.decimal ​

pl.duration ​

pl.enumType ​

pl.escapeRegex ​

pl.excludeCols ​

pl.excludeDataTypes ​

pl.explainAll ​

pl.extensionType ​

pl.field ​

pl.firstCol ​

pl.firstValue ​

pl.fold ​

pl.format ​

pl.fromEpoch ​

pl.ifElse ​

pl.implode ​

pl.intRange ​

pl.intRangeAsSeries ​

pl.intRanges ​

pl.intRangesAsSeries ​

pl.lastCol ​

pl

Properties & Indexers

Module Functions

pl.alias

pl.alignDataFrames

pl.alignDataFramesAsync

pl.alignLazyFrames

pl.all

pl.allHorizontal

pl.allOf

pl.any

pl.anyHorizontal

pl.arctan2

pl.argSortBy

pl.argWhere

pl.argWhereAsSeries

pl.array

pl.asLazy

pl.asStruct

pl.businessDayCount

pl.categorical

pl.categories

pl.coalesce

pl.coalesceAsSeries

pl.col

pl.collect

pl.collectAll

pl.collectAllAsync

pl.collectWithEngine

pl.cols

pl.combineDateAndTime

pl.combineDateAndTimeUnit

pl.concatArray

pl.concatDataFrame

pl.concatExpr

pl.concatLazyFrame

pl.concatList

pl.concatSeries

pl.concatString

pl.corrPearson

pl.corrPearsonAsSeries

pl.corrSpearman

pl.corrSpearmanAsSeries

pl.count

pl.cov

pl.covAsSeries

pl.cumCount

pl.cumSum

pl.dataTypeOf

pl.dataframe

pl.dateRange

pl.dateRangeAsSeries

pl.dateRanges

pl.dateRangesAsSeries

pl.datetime

pl.datetimeRange

pl.datetimeRangeAsSeries

pl.datetimeRanges

pl.datetimeRangesAsSeries

pl.decimal

pl.duration

pl.enumType

pl.escapeRegex

pl.excludeCols

pl.excludeDataTypes

pl.explainAll

pl.extensionType

pl.field

pl.firstCol

pl.firstValue

pl.fold

pl.format

pl.fromEpoch

pl.ifElse

pl.implode

pl.intRange

pl.intRangeAsSeries

pl.intRanges

pl.intRangesAsSeries

pl.lastCol