Struct ProjectionMapping 

pub struct ProjectionMapping {
    map: IndexMap<Arc<dyn PhysicalExpr>, ProjectionTargets>,
}

Stores the mapping between source expressions and target expressions for a projection.

Fields

map: IndexMap<Arc<dyn PhysicalExpr>, ProjectionTargets>

Implementations

impl ProjectionMapping

pub fn try_new( expr: impl IntoIterator<Item = (Arc<dyn PhysicalExpr>, String)>, input_schema: &Arc<Schema>, ) -> Result<ProjectionMapping, DataFusionError>

Constructs the mapping between a projection’s input and output expressions.

For example, given the input projection expressions (a + b, c + d) and an output schema with two columns "c + d" and "a + b", the projection mapping would be:

 [0]: (c + d, [(col("c + d"), 0)])
 [1]: (a + b, [(col("a + b"), 1)])

where col("c + d") means the column named "c + d".

pub fn from_indices( indices: &[usize], schema: &Arc<Schema>, ) -> Result<ProjectionMapping, DataFusionError>

Constructs a subset mapping using the provided indices.

This is used when the output is a subset of the input without any other transformations. The indices are for columns in the schema.

Methods from Deref<Target = IndexMap<Arc<dyn PhysicalExpr>, ProjectionTargets>>

pub fn capacity(&self) -> usize

Return the number of elements the map can hold without reallocating.

This number is a lower bound; the map might be able to hold more, but is guaranteed to be able to hold at least this many.

Computes in O(1) time.

pub fn hasher(&self) -> &S

Return a reference to the map’s BuildHasher.

pub fn len(&self) -> usize

Return the number of key-value pairs in the map.

Computes in O(1) time.

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Computes in O(1) time.

pub fn iter(&self) -> Iter<'_, K, V>

Return an iterator over the key-value pairs of the map, in their order

pub fn keys(&self) -> Keys<'_, K, V>

Return an iterator over the keys of the map, in their order

pub fn values(&self) -> Values<'_, K, V>

Return an iterator over the values of the map, in their order

pub fn contains_key<Q>(&self, key: &Q) -> bool

where Q: Hash + Equivalent<K> + ?Sized,

Return true if an equivalent to key exists in the map.

Computes in O(1) time (average).

pub fn get<Q>(&self, key: &Q) -> Option<&V>

where Q: Hash + Equivalent<K> + ?Sized,

Return a reference to the stored value for key, if it is present, else None.

Computes in O(1) time (average).

pub fn get_key_value<Q>(&self, key: &Q) -> Option<(&K, &V)>

where Q: Hash + Equivalent<K> + ?Sized,

Return references to the stored key-value pair for the lookup key, if it is present, else None.

Computes in O(1) time (average).

pub fn get_full<Q>(&self, key: &Q) -> Option<(usize, &K, &V)>

where Q: Hash + Equivalent<K> + ?Sized,

Return the index with references to the stored key-value pair for the lookup key, if it is present, else None.

Computes in O(1) time (average).

pub fn get_index_of<Q>(&self, key: &Q) -> Option<usize>

where Q: Hash + Equivalent<K> + ?Sized,

Return the item index for key, if it is present, else None.

Computes in O(1) time (average).

pub fn binary_search_keys(&self, x: &K) -> Result<usize, usize>

where K: Ord,

Search over a sorted map for a key.

Returns the position where that key is present, or the position where it can be inserted to maintain the sort. See slice::binary_search for more details.

Computes in O(log(n)) time, which is notably less scalable than looking the key up using [get_index_of][IndexMap::get_index_of], but this can also position missing keys.

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>

where F: FnMut(&'a K, &'a V) -> Ordering,

Search over a sorted map with a comparator function.

Returns the position where that value is present, or the position where it can be inserted to maintain the sort. See slice::binary_search_by for more details.

Computes in O(log(n)) time.

pub fn binary_search_by_key<'a, B, F>( &'a self, b: &B, f: F, ) -> Result<usize, usize>

where F: FnMut(&'a K, &'a V) -> B, B: Ord,

Search over a sorted map with an extraction function.

Returns the position where that value is present, or the position where it can be inserted to maintain the sort. See slice::binary_search_by_key for more details.

Computes in O(log(n)) time.

pub fn is_sorted(&self) -> bool

where K: PartialOrd,

Checks if the keys of this map are sorted.

pub fn is_sorted_by<'a, F>(&'a self, cmp: F) -> bool

where F: FnMut(&'a K, &'a V, &'a K, &'a V) -> bool,

Checks if this map is sorted using the given comparator function.

pub fn is_sorted_by_key<'a, F, T>(&'a self, sort_key: F) -> bool

where F: FnMut(&'a K, &'a V) -> T, T: PartialOrd,

Checks if this map is sorted using the given sort-key function.

pub fn partition_point<P>(&self, pred: P) -> usize

where P: FnMut(&K, &V) -> bool,

Returns the index of the partition point of a sorted map according to the given predicate (the index of the first element of the second partition).

See slice::partition_point for more details.

Computes in O(log(n)) time.

pub fn as_slice(&self) -> &Slice<K, V>

Returns a slice of all the key-value pairs in the map.

Computes in O(1) time.

pub fn get_index(&self, index: usize) -> Option<(&K, &V)>

Get a key-value pair by index

Valid indices are 0 <= index < self.len().

Computes in O(1) time.

pub fn get_range<R>(&self, range: R) -> Option<&Slice<K, V>>

where R: RangeBounds<usize>,

Returns a slice of key-value pairs in the given range of indices.

Valid indices are 0 <= index < self.len().

Computes in O(1) time.

pub fn first(&self) -> Option<(&K, &V)>

Get the first key-value pair

Computes in O(1) time.

pub fn last(&self) -> Option<(&K, &V)>

Get the last key-value pair

Computes in O(1) time.

Trait Implementations

impl Clone for ProjectionMapping

fn clone(&self) -> ProjectionMapping

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProjectionMapping

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

Formats the value using the given formatter.

impl Deref for ProjectionMapping

type Target = IndexMap<Arc<dyn PhysicalExpr>, ProjectionTargets>

The resulting type after dereferencing.

fn deref(&self) -> &<ProjectionMapping as Deref>::Target

Dereferences the value.

impl FromIterator<(Arc<dyn PhysicalExpr>, ProjectionTargets)> for ProjectionMapping

fn from_iter<T>(iter: T) -> ProjectionMapping

where T: IntoIterator<Item = (Arc<dyn PhysicalExpr>, ProjectionTargets)>,

Creates a value from an iterator.