Struct polars::prelude::ArrowSchema

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

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.

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§fields: Vec<Field>

The fields composing this schema.

§metadata: BTreeMap<String, String>

Optional metadata.

Implementations§

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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.

Trait Implementations§

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impl Clone for ArrowSchema

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fn clone(&self) -> ArrowSchema

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for ArrowSchema

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

Formats the value using the given formatter. Read more
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impl Default for ArrowSchema

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fn default() -> ArrowSchema

Returns the “default value” for a type. Read more
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impl From<&ArrowSchema> for DataFrame

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fn from(schema: &ArrowSchema) -> DataFrame

Converts to this type from the input type.
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impl From<&ArrowSchema> for Schema

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fn from(value: &ArrowSchema) -> Schema

Converts to this type from the input type.
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impl From<ArrowSchema> for Schema

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fn from(value: ArrowSchema) -> Schema

Converts to this type from the input type.
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impl From<Vec<Field>> for ArrowSchema

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

Converts to this type from the input type.
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impl IndexOfSchema for ArrowSchema

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

Get the index of a column by name.
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fn get_names(&self) -> Vec<&str>

Get a vector of all column names.
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fn try_index_of(&self, name: &str) -> Result<usize, PolarsError>

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impl PartialEq for ArrowSchema

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Eq for ArrowSchema

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impl StructuralPartialEq for ArrowSchema

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Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> DynClone for T
where T: Clone,

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fn __clone_box(&self, _: Private) -> *mut ()

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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V