Struct polars_core::prelude::ArrowSchema

pub struct ArrowSchema {
    pub fields: Vec<Field>,
    pub metadata: BTreeMap<String, String>,
}

An ordered sequence of Fields with associated Metadata.

ArrowSchema is an abstraction used to read from, and write to, Arrow IPC format, Apache Parquet, and Apache Avro. All these formats have a concept of a schema with fields and metadata.

Fields

fields: Vec<Field>

The fields composing this schema.

metadata: BTreeMap<String, String>

Optional metadata.

Implementations

impl ArrowSchema

pub fn with_metadata(self, metadata: BTreeMap<String, String>) -> ArrowSchema

Attaches a Metadata to ArrowSchema

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn filter<F>(self, predicate: F) -> ArrowSchema

where F: Fn(usize, &Field) -> bool,

Returns a new ArrowSchema with a subset of all fields whose predicate evaluates to true.

pub fn try_project(&self, indices: &[usize]) -> Result<ArrowSchema, PolarsError>

Trait Implementations

impl Clone for ArrowSchema

fn clone(&self) -> ArrowSchema

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ArrowSchema

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for ArrowSchema

fn default() -> ArrowSchema

Returns the “default value” for a type.

impl From<&ArrowSchema> for Schema

fn from(value: &ArrowSchema) -> Self

Converts to this type from the input type.

impl From<ArrowSchema> for Schema

fn from(value: ArrowSchema) -> Self

Converts to this type from the input type.

impl From<Vec<Field>> for ArrowSchema

fn from(fields: Vec<Field>) -> ArrowSchema

Converts to this type from the input type.

impl IndexOfSchema for ArrowSchema

fn index_of(&self, name: &str) -> Option<usize>

Get the index of a column by name.

fn get_names(&self) -> Vec<&str>

Get a vector of all column names.

fn try_index_of(&self, name: &str) -> PolarsResult<usize>

impl PartialEq for ArrowSchema

fn eq(&self, other: &ArrowSchema) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl SchemaNamesAndDtypes for ArrowSchema

const IS_ARROW: bool = true

type DataType = ArrowDataType

fn get_names_and_dtypes(&self) -> Vec<(&str, Self::DataType)>

Get a vector of (name, dtype) pairs

impl Eq for ArrowSchema

impl StructuralPartialEq for ArrowSchema