DataTypeExpr

Namespace: Polars.CSharp

A lazily instantiated DataType that can be used in an Expr. This expression is made to represent a DataType that can be used to reference a datatype in a lazy context.

Sub-namespaces

Sub-namespace	Page	Description
.Array	DataTypeExpr.Array	-
.List	DataTypeExpr.List	-
.Struct	DataTypeExpr.Struct	-

Instance Methods

Clone

Clone DataTypeExpr

public DataTypeExpr Clone()

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CollectDataType

Materialize the DataTypeExpr in a specific context.

Materialize the DataTypeExpr using a DataFrame's schema as context.

Materialize the DataTypeExpr using a LazyFrame's schema as context.

public DataType CollectDataType(PolarsSchema schema)
public DataType CollectDataType(DataFrame df)
public DataType CollectDataType(LazyFrame lf)

Parameters

Name	Type	Description
schema	PolarsSchema	-
df	DataFrame	-
lf	LazyFrame	-

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DefaultValue

Get a default value of a specific type.

Integers and floats are their zero value as default, unless otherwise specified

Temporals are a physical zero as default

Decimal is zero as default

String and Binary are an empty string

List is an empty list, unless otherwise specified

Array is the inner default value repeated over the shape

Struct is the inner default value for all fields

Enum is the first category if it exists

Null, Object and Categorical are null.

public Expr DefaultValue(int n = 1, bool numericToOne = false, int numListValues = 0)

Parameters

Name	Type	Description
n	int	Number of types you want the value
numericToOne	bool	Use 1 instead of 0 as the default value for numeric types
numListValues	int	The amount of values a list contains

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Display

Get a formatted version of the output DataType.

public Expr Display()

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InnerDataType

Get the inner DataType of a List or Array.

public DataTypeExpr InnerDataType()

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Matches

Get whether the output DataType is matches a certain selector.

public Expr Matches(Selector selector)

Parameters

Name	Type	Description
selector	Selector	-

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ToLiteral

Convert DataTypeExpr into DataType Literal. Returns null if the expression is not a literal (e.g. SelfDtype).

public DataType ToLiteral()

Returns: A DataType instance or null.

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ToSignedInteger

Get the signed integer version of the same bitsize.

public DataTypeExpr ToSignedInteger()

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ToUnsignedInteger

Get the unsigned integer version of the same bitsize.

public DataTypeExpr ToUnsignedInteger()

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WrapInArray

Get the DataType wrapped in an array.

public DataTypeExpr WrapInArray(uint width)

Parameters

Name	Type	Description
width	uint	Array Width

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WrapInList

Get the DataType wrapped in a list.

public DataTypeExpr WrapInList()

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