Struct arrow::datatypes::Field

pub struct Field {
    name: String,
    data_type: DataType,
    nullable: bool,
    dict_id: i64,
    dict_is_ordered: bool,
    metadata: HashMap<String, String>,
}
Expand description

Describes a single column in a Schema.

A Schema is an ordered collection of Field objects.

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§name: String§data_type: DataType§nullable: bool§dict_id: i64§dict_is_ordered: bool§metadata: HashMap<String, String>

Implementations§

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impl Field

pub fn new( name: impl Into<String>, data_type: DataType, nullable: bool ) -> Field

Creates a new field with the given name, type, and nullability

pub fn new_list_field(data_type: DataType, nullable: bool) -> Field

Creates a new Field suitable for DataType::List and DataType::LargeList

While not required, this method follows the convention of naming the Field "item".

§Example
assert_eq!(
  Field::new("item", DataType::Int32, true),
  Field::new_list_field(DataType::Int32, true)
);

pub fn new_dict( name: impl Into<String>, data_type: DataType, nullable: bool, dict_id: i64, dict_is_ordered: bool ) -> Field

Creates a new field that has additional dictionary information

pub fn new_dictionary( name: impl Into<String>, key: DataType, value: DataType, nullable: bool ) -> Field

Create a new Field with DataType::Dictionary

Use Self::new_dict for more advanced dictionary options

§Panics

Panics if !key.is_dictionary_key_type

pub fn new_struct( name: impl Into<String>, fields: impl Into<Fields>, nullable: bool ) -> Field

Create a new Field with DataType::Struct

pub fn new_list( name: impl Into<String>, value: impl Into<Arc<Field>>, nullable: bool ) -> Field

Create a new Field with DataType::List

pub fn new_large_list( name: impl Into<String>, value: impl Into<Arc<Field>>, nullable: bool ) -> Field

Create a new Field with DataType::LargeList

pub fn new_fixed_size_list( name: impl Into<String>, value: impl Into<Arc<Field>>, size: i32, nullable: bool ) -> Field

Create a new Field with DataType::FixedSizeList

pub fn new_map( name: impl Into<String>, entries: impl Into<String>, keys: impl Into<Arc<Field>>, values: impl Into<Arc<Field>>, sorted: bool, nullable: bool ) -> Field

Create a new Field with DataType::Map

pub fn new_union<S, F, T>( name: S, type_ids: T, fields: F, mode: UnionMode ) -> Field
where S: Into<String>, F: IntoIterator, <F as IntoIterator>::Item: Into<Arc<Field>>, T: IntoIterator<Item = i8>,

Create a new Field with DataType::Union

  • name: the name of the DataType::Union field
  • type_ids: the union type ids
  • fields: the union fields
  • mode: the union mode

pub fn set_metadata(&mut self, metadata: HashMap<String, String>)

Sets the Field’s optional custom metadata.

pub fn with_metadata(self, metadata: HashMap<String, String>) -> Field

Sets the metadata of this Field to be metadata and returns self

pub const fn metadata(&self) -> &HashMap<String, String>

Returns the immutable reference to the Field’s optional custom metadata.

pub const fn name(&self) -> &String

Returns an immutable reference to the Field’s name.

pub fn with_name(self, name: impl Into<String>) -> Field

Set the name of the Field and returns self.

let field = Field::new("c1", DataType::Int64, false)
   .with_name("c2");

assert_eq!(field.name(), "c2");

pub const fn data_type(&self) -> &DataType

Returns an immutable reference to the Field’s DataType.

pub fn with_data_type(self, data_type: DataType) -> Field

Set DataType of the Field and returns self.

let field = Field::new("c1", DataType::Int64, false)
   .with_data_type(DataType::Utf8);

assert_eq!(field.data_type(), &DataType::Utf8);

pub const fn is_nullable(&self) -> bool

Indicates whether this Field supports null values.

pub fn with_nullable(self, nullable: bool) -> Field

Set nullable of the Field and returns self.

let field = Field::new("c1", DataType::Int64, false)
   .with_nullable(true);

assert_eq!(field.is_nullable(), true);

pub const fn dict_id(&self) -> Option<i64>

Returns the dictionary ID, if this is a dictionary type.

pub const fn dict_is_ordered(&self) -> Option<bool>

Returns whether this Field’s dictionary is ordered, if this is a dictionary type.

pub fn try_merge(&mut self, from: &Field) -> Result<(), ArrowError>

Merge this field into self if it is compatible.

Struct fields are merged recursively.

NOTE: self may be updated to a partial / unexpected state in case of merge failure.

Example:

let mut field = Field::new("c1", DataType::Int64, false);
assert!(field.try_merge(&Field::new("c1", DataType::Int64, true)).is_ok());
assert!(field.is_nullable());

pub fn contains(&self, other: &Field) -> bool

Check to see if self is a superset of other field. Superset is defined as:

  • if nullability doesn’t match, self needs to be nullable
  • self.metadata is a superset of other.metadata
  • all other fields are equal

pub fn size(&self) -> usize

Return size of this instance in bytes.

Includes the size of Self.

Trait Implementations§

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impl Clone for Field

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fn clone(&self) -> Field

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 Field

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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<'de> Deserialize<'de> for Field

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fn deserialize<__D>( __deserializer: __D ) -> Result<Field, <__D as Deserializer<'de>>::Error>
where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl Display for Field

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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 Extend<Field> for SchemaBuilder

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fn extend<T>(&mut self, iter: T)
where T: IntoIterator<Item = Field>,

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<'a> From<Field<'a>> for Field

Convert an IPC Field to Arrow Field

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fn from(field: Field<'_>) -> Field

Converts to this type from the input type.
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impl FromIterator<Field> for Fields

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fn from_iter<T>(iter: T) -> Fields
where T: IntoIterator<Item = Field>,

Creates a value from an iterator. Read more
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impl FromPyArrow for Field

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fn from_pyarrow_bound(value: &Bound<'_, PyAny>) -> PyResult<Self>

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fn from_pyarrow(value: &PyAny) -> PyResult<Self>

👎Deprecated since 52.0.0: Use from_pyarrow_bound
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impl Hash for Field

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fn hash<H>(&self, state: &mut H)
where H: Hasher,

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for Field

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fn cmp(&self, other: &Field) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl PartialEq for Field

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fn eq(&self, other: &Field) -> 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 PartialOrd for Field

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fn partial_cmp(&self, other: &Field) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Serialize for Field

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fn serialize<__S>( &self, __serializer: __S ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>
where __S: Serializer,

Serialize this value into the given Serde serializer. Read more
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impl ToPyArrow for Field

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fn to_pyarrow(&self, py: Python<'_>) -> PyResult<PyObject>

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impl TryFrom<&FFI_ArrowSchema> for Field

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type Error = ArrowError

The type returned in the event of a conversion error.
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fn try_from(c_schema: &FFI_ArrowSchema) -> Result<Field, ArrowError>

Performs the conversion.
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impl TryFrom<&Field> for FFI_ArrowSchema

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type Error = ArrowError

The type returned in the event of a conversion error.
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fn try_from(field: &Field) -> Result<FFI_ArrowSchema, ArrowError>

Performs the conversion.
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impl TryFrom<Field> for FFI_ArrowSchema

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type Error = ArrowError

The type returned in the event of a conversion error.
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fn try_from(field: Field) -> Result<FFI_ArrowSchema, ArrowError>

Performs the conversion.
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impl Eq for Field

Auto Trait Implementations§

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impl Freeze for Field

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impl RefUnwindSafe for Field

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impl Send for Field

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impl Sync for Field

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impl Unpin for Field

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impl UnwindSafe for Field

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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<Q, K> Comparable<K> for Q
where Q: Ord + ?Sized, K: Borrow<Q> + ?Sized,

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fn compare(&self, key: &K) -> Ordering

Compare self to key and return their ordering.
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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> IntoPyArrow for T
where T: ToPyArrow,

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fn into_pyarrow(self, py: Python<'_>) -> Result<Py<PyAny>, PyErr>

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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> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. 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

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impl<T> Allocation for T
where T: RefUnwindSafe + Send + Sync,

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impl<T> DeserializeOwned for T
where T: for<'de> Deserialize<'de>,

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impl<T> Ungil for T
where T: Send,