Enum Expr

pub enum Expr {
Show 28 variants
    Alias(Arc<Expr>, PlSmallStr),
    Column(PlSmallStr),
    Columns(Arc<[PlSmallStr]>),
    DtypeColumn(Vec<DataType>),
    IndexColumn(Arc<[i64]>),
    Literal(LiteralValue),
    BinaryExpr {
        left: Arc<Expr>,
        op: Operator,
        right: Arc<Expr>,
    },
    Cast {
        expr: Arc<Expr>,
        dtype: DataType,
        options: CastOptions,
    },
    Sort {
        expr: Arc<Expr>,
        options: SortOptions,
    },
    Gather {
        expr: Arc<Expr>,
        idx: Arc<Expr>,
        returns_scalar: bool,
    },
    SortBy {
        expr: Arc<Expr>,
        by: Vec<Expr>,
        sort_options: SortMultipleOptions,
    },
    Agg(AggExpr),
    Ternary {
        predicate: Arc<Expr>,
        truthy: Arc<Expr>,
        falsy: Arc<Expr>,
    },
    Function {
        input: Vec<Expr>,
        function: FunctionExpr,
        options: FunctionOptions,
    },
    Explode(Arc<Expr>),
    Filter {
        input: Arc<Expr>,
        by: Arc<Expr>,
    },
    Window {
        function: Arc<Expr>,
        partition_by: Vec<Expr>,
        order_by: Option<(Arc<Expr>, SortOptions)>,
        options: WindowType,
    },
    Wildcard,
    Slice {
        input: Arc<Expr>,
        offset: Arc<Expr>,
        length: Arc<Expr>,
    },
    Exclude(Arc<Expr>, Vec<Excluded>),
    KeepName(Arc<Expr>),
    Len,
    Nth(i64),
    RenameAlias {
        function: SpecialEq<Arc<dyn RenameAliasFn>>,
        expr: Arc<Expr>,
    },
    Field(Arc<[PlSmallStr]>),
    AnonymousFunction {
        input: Vec<Expr>,
        function: LazySerde<SpecialEq<Arc<dyn ColumnsUdf>>>,
        output_type: SpecialEq<Arc<dyn FunctionOutputField>>,
        options: FunctionOptions,
    },
    SubPlan(SpecialEq<Arc<DslPlan>>, Vec<String>),
    Selector(Selector),
}

Expand description

Expressions that can be used in various contexts.

Queries consist of multiple expressions. When using the polars lazy API, don’t construct an Expr directly; instead, create one using the functions in the polars_lazy::dsl module. See that module’s docs for more info.

Variants§

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BinaryExpr

Fields

§left: Arc<Expr>

§op: Operator

§right: Arc<Expr>

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Cast

Fields

§expr: Arc<Expr>

§dtype: DataType

§options: CastOptions

§

Sort

Fields

§expr: Arc<Expr>

§options: SortOptions

§

Gather

Fields

§expr: Arc<Expr>

§idx: Arc<Expr>

§returns_scalar: bool

§

SortBy

Fields

§expr: Arc<Expr>

§by: Vec<Expr>

§sort_options: SortMultipleOptions

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Agg(AggExpr)

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Ternary

A ternary operation if true then “foo” else “bar”

Fields

§predicate: Arc<Expr>

§truthy: Arc<Expr>

§falsy: Arc<Expr>

§

Function

Fields

§input: Vec<Expr>

function arguments

§function: FunctionExpr

function to apply

§options: FunctionOptions

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Explode(Arc<Expr>)

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Filter

Fields

§input: Arc<Expr>

§by: Arc<Expr>

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Window

Polars flavored window functions.

Fields

§function: Arc<Expr>

Also has the input. i.e. avg(“foo”)

§partition_by: Vec<Expr>

§order_by: Option<(Arc<Expr>, SortOptions)>

§options: WindowType

§

Wildcard

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Slice

Fields

§input: Arc<Expr>

§offset: Arc<Expr>

length is not yet known so we accept negative offsets

§length: Arc<Expr>

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Exclude(Arc<Expr>, Vec<Excluded>)

Can be used in a select statement to exclude a column from selection TODO: See if we can replace Vec<Excluded> with Arc<Excluded>

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KeepName(Arc<Expr>)

Set root name as Alias

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Len

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Nth(i64)

Take the nth column in the DataFrame

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RenameAlias

Fields

§function: SpecialEq<Arc<dyn RenameAliasFn>>

§expr: Arc<Expr>

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Field(Arc<[PlSmallStr]>)

Available on crate feature dtype-struct only.

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AnonymousFunction

Fields

§input: Vec<Expr>

function arguments

§function: LazySerde<SpecialEq<Arc<dyn ColumnsUdf>>>

function to apply

§output_type: SpecialEq<Arc<dyn FunctionOutputField>>

output dtype of the function

§options: FunctionOptions

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SubPlan(SpecialEq<Arc<DslPlan>>, Vec<String>)

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Selector(Selector)

Expressions in this node should only be expanding e.g. Expr::Columns Expr::Dtypes Expr::Wildcard Expr::Exclude

Implementations§

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impl Expr

pub fn floor_div(self, rhs: Expr) -> Expr

Floor divide self by rhs.

pub fn pow<E>(self, exponent: E) -> Expr
where E: Into<Expr>,

Raise expression to the power exponent

pub fn sqrt(self) -> Expr

Compute the square root of the given expression