arrow_array/array/
struct_array.rs

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5// to you under the Apache License, Version 2.0 (the
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8//
9//   http://www.apache.org/licenses/LICENSE-2.0
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14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::array::print_long_array;
19use crate::{Array, ArrayRef, RecordBatch, make_array, new_null_array};
20use arrow_buffer::{BooleanBuffer, Buffer, NullBuffer};
21use arrow_data::{ArrayData, ArrayDataBuilder};
22use arrow_schema::{ArrowError, DataType, Field, FieldRef, Fields};
23use std::sync::Arc;
24use std::{any::Any, ops::Index};
25
26/// An array of [structs](https://arrow.apache.org/docs/format/Columnar.html#struct-layout)
27///
28/// Each child (called *field*) is represented by a separate array.
29///
30/// # Comparison with [RecordBatch]
31///
32/// Both [`RecordBatch`] and [`StructArray`] represent a collection of columns / arrays with the
33/// same length.
34///
35/// However, there are a couple of key differences:
36///
37/// * [`StructArray`] can be nested within other [`Array`], including itself
38/// * [`RecordBatch`] can contain top-level metadata on its associated [`Schema`][arrow_schema::Schema]
39/// * [`StructArray`] can contain top-level nulls, i.e. `null`
40/// * [`RecordBatch`] can only represent nulls in its child columns, i.e. `{"field": null}`
41///
42/// [`StructArray`] is therefore a more general data container than [`RecordBatch`], and as such
43/// code that needs to handle both will typically share an implementation in terms of
44/// [`StructArray`] and convert to/from [`RecordBatch`] as necessary.
45///
46/// [`From`] implementations are provided to facilitate this conversion, however, converting
47/// from a [`StructArray`] containing top-level nulls to a [`RecordBatch`] will panic, as there
48/// is no way to preserve them.
49///
50/// # Example: Create an array from a vector of fields
51///
52/// ```
53/// use std::sync::Arc;
54/// use arrow_array::{Array, ArrayRef, BooleanArray, Int32Array, StructArray};
55/// use arrow_schema::{DataType, Field};
56///
57/// let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
58/// let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));
59///
60/// let struct_array = StructArray::from(vec![
61///     (
62///         Arc::new(Field::new("b", DataType::Boolean, false)),
63///         boolean.clone() as ArrayRef,
64///     ),
65///     (
66///         Arc::new(Field::new("c", DataType::Int32, false)),
67///         int.clone() as ArrayRef,
68///     ),
69/// ]);
70/// assert_eq!(struct_array.column(0).as_ref(), boolean.as_ref());
71/// assert_eq!(struct_array.column(1).as_ref(), int.as_ref());
72/// assert_eq!(4, struct_array.len());
73/// assert_eq!(0, struct_array.null_count());
74/// assert_eq!(0, struct_array.offset());
75/// ```
76#[derive(Clone)]
77pub struct StructArray {
78    len: usize,
79    data_type: DataType,
80    nulls: Option<NullBuffer>,
81    fields: Vec<ArrayRef>,
82}
83
84impl StructArray {
85    /// Create a new [`StructArray`] from the provided parts, panicking on failure
86    ///
87    /// # Panics
88    ///
89    /// Panics if [`Self::try_new`] returns an error
90    pub fn new(fields: Fields, arrays: Vec<ArrayRef>, nulls: Option<NullBuffer>) -> Self {
91        Self::try_new(fields, arrays, nulls).unwrap()
92    }
93
94    /// Create a new [`StructArray`] from the provided parts, returning an error on failure
95    ///
96    /// The length will be inferred from the length of the child arrays.  Returns an error if
97    /// there are no child arrays.  Consider using [`Self::try_new_with_length`] if the length
98    /// is known to avoid this.
99    ///
100    /// # Errors
101    ///
102    /// Errors if
103    ///
104    /// * `fields.len() == 0`
105    /// * Any reason that [`Self::try_new_with_length`] would error
106    pub fn try_new(
107        fields: Fields,
108        arrays: Vec<ArrayRef>,
109        nulls: Option<NullBuffer>,
110    ) -> Result<Self, ArrowError> {
111        let len = arrays.first().map(|x| x.len()).ok_or_else(||ArrowError::InvalidArgumentError("use StructArray::try_new_with_length or StructArray::new_empty_fields to create a struct array with no fields so that the length can be set correctly".to_string()))?;
112
113        Self::try_new_with_length(fields, arrays, nulls, len)
114    }
115
116    /// Create a new [`StructArray`] from the provided parts, returning an error on failure
117    ///
118    /// # Errors
119    ///
120    /// Errors if
121    ///
122    /// * `fields.len() != arrays.len()`
123    /// * `fields[i].data_type() != arrays[i].data_type()`
124    /// * `arrays[i].len() != arrays[j].len()`
125    /// * `arrays[i].len() != nulls.len()`
126    /// * `!fields[i].is_nullable() && !nulls.contains(arrays[i].nulls())`
127    pub fn try_new_with_length(
128        fields: Fields,
129        arrays: Vec<ArrayRef>,
130        nulls: Option<NullBuffer>,
131        len: usize,
132    ) -> Result<Self, ArrowError> {
133        if fields.len() != arrays.len() {
134            return Err(ArrowError::InvalidArgumentError(format!(
135                "Incorrect number of arrays for StructArray fields, expected {} got {}",
136                fields.len(),
137                arrays.len()
138            )));
139        }
140
141        if let Some(n) = nulls.as_ref() {
142            if n.len() != len {
143                return Err(ArrowError::InvalidArgumentError(format!(
144                    "Incorrect number of nulls for StructArray, expected {len} got {}",
145                    n.len(),
146                )));
147            }
148        }
149
150        for (f, a) in fields.iter().zip(&arrays) {
151            if f.data_type() != a.data_type() {
152                return Err(ArrowError::InvalidArgumentError(format!(
153                    "Incorrect datatype for StructArray field {:?}, expected {} got {}",
154                    f.name(),
155                    f.data_type(),
156                    a.data_type()
157                )));
158            }
159
160            if a.len() != len {
161                return Err(ArrowError::InvalidArgumentError(format!(
162                    "Incorrect array length for StructArray field {:?}, expected {} got {}",
163                    f.name(),
164                    len,
165                    a.len()
166                )));
167            }
168
169            if !f.is_nullable() {
170                if let Some(a) = a.logical_nulls() {
171                    if !nulls.as_ref().map(|n| n.contains(&a)).unwrap_or_default()
172                        && a.null_count() > 0
173                    {
174                        return Err(ArrowError::InvalidArgumentError(format!(
175                            "Found unmasked nulls for non-nullable StructArray field {:?}",
176                            f.name()
177                        )));
178                    }
179                }
180            }
181        }
182
183        Ok(Self {
184            len,
185            data_type: DataType::Struct(fields),
186            nulls: nulls.filter(|n| n.null_count() > 0),
187            fields: arrays,
188        })
189    }
190
191    /// Create a new [`StructArray`] of length `len` where all values are null
192    pub fn new_null(fields: Fields, len: usize) -> Self {
193        let arrays = fields
194            .iter()
195            .map(|f| new_null_array(f.data_type(), len))
196            .collect();
197
198        Self {
199            len,
200            data_type: DataType::Struct(fields),
201            nulls: Some(NullBuffer::new_null(len)),
202            fields: arrays,
203        }
204    }
205
206    /// Create a new [`StructArray`] from the provided parts without validation
207    ///
208    /// The length will be inferred from the length of the child arrays.  Panics if there are no
209    /// child arrays.  Consider using [`Self::new_unchecked_with_length`] if the length is known
210    /// to avoid this.
211    ///
212    /// # Safety
213    ///
214    /// Safe if [`Self::new`] would not panic with the given arguments
215    pub unsafe fn new_unchecked(
216        fields: Fields,
217        arrays: Vec<ArrayRef>,
218        nulls: Option<NullBuffer>,
219    ) -> Self {
220        if cfg!(feature = "force_validate") {
221            return Self::new(fields, arrays, nulls);
222        }
223
224        let len = arrays.first().map(|x| x.len()).expect(
225            "cannot use StructArray::new_unchecked if there are no fields, length is unknown",
226        );
227        Self {
228            len,
229            data_type: DataType::Struct(fields),
230            nulls,
231            fields: arrays,
232        }
233    }
234
235    /// Create a new [`StructArray`] from the provided parts without validation
236    ///
237    /// # Safety
238    ///
239    /// Safe if [`Self::new`] would not panic with the given arguments
240    pub unsafe fn new_unchecked_with_length(
241        fields: Fields,
242        arrays: Vec<ArrayRef>,
243        nulls: Option<NullBuffer>,
244        len: usize,
245    ) -> Self {
246        if cfg!(feature = "force_validate") {
247            return Self::try_new_with_length(fields, arrays, nulls, len).unwrap();
248        }
249
250        Self {
251            len,
252            data_type: DataType::Struct(fields),
253            nulls,
254            fields: arrays,
255        }
256    }
257
258    /// Create a new [`StructArray`] containing no fields
259    ///
260    /// # Panics
261    ///
262    /// If `len != nulls.len()`
263    pub fn new_empty_fields(len: usize, nulls: Option<NullBuffer>) -> Self {
264        if let Some(n) = &nulls {
265            assert_eq!(len, n.len())
266        }
267        Self {
268            len,
269            data_type: DataType::Struct(Fields::empty()),
270            fields: vec![],
271            nulls,
272        }
273    }
274
275    /// Deconstruct this array into its constituent parts
276    pub fn into_parts(self) -> (Fields, Vec<ArrayRef>, Option<NullBuffer>) {
277        let f = match self.data_type {
278            DataType::Struct(f) => f,
279            _ => unreachable!(),
280        };
281        (f, self.fields, self.nulls)
282    }
283
284    /// Returns the field at `pos`.
285    pub fn column(&self, pos: usize) -> &ArrayRef {
286        &self.fields[pos]
287    }
288
289    /// Return the number of fields in this struct array
290    pub fn num_columns(&self) -> usize {
291        self.fields.len()
292    }
293
294    /// Returns the fields of the struct array
295    pub fn columns(&self) -> &[ArrayRef] {
296        &self.fields
297    }
298
299    /// Return field names in this struct array
300    pub fn column_names(&self) -> Vec<&str> {
301        match self.data_type() {
302            DataType::Struct(fields) => fields
303                .iter()
304                .map(|f| f.name().as_str())
305                .collect::<Vec<&str>>(),
306            _ => unreachable!("Struct array's data type is not struct!"),
307        }
308    }
309
310    /// Returns the [`Fields`] of this [`StructArray`]
311    pub fn fields(&self) -> &Fields {
312        match self.data_type() {
313            DataType::Struct(f) => f,
314            _ => unreachable!(),
315        }
316    }
317
318    /// Return child array whose field name equals to column_name
319    ///
320    /// Note: A schema can currently have duplicate field names, in which case
321    /// the first field will always be selected.
322    /// This issue will be addressed in [ARROW-11178](https://issues.apache.org/jira/browse/ARROW-11178)
323    pub fn column_by_name(&self, column_name: &str) -> Option<&ArrayRef> {
324        self.column_names()
325            .iter()
326            .position(|c| c == &column_name)
327            .map(|pos| self.column(pos))
328    }
329
330    /// Returns a zero-copy slice of this array with the indicated offset and length.
331    pub fn slice(&self, offset: usize, len: usize) -> Self {
332        assert!(
333            offset.saturating_add(len) <= self.len,
334            "the length + offset of the sliced StructArray cannot exceed the existing length"
335        );
336
337        let fields = self.fields.iter().map(|a| a.slice(offset, len)).collect();
338
339        Self {
340            len,
341            data_type: self.data_type.clone(),
342            nulls: self.nulls.as_ref().map(|n| n.slice(offset, len)),
343            fields,
344        }
345    }
346
347    /// Returns the children of this [`StructArray`] with the struct's validity
348    /// bitmap AND'd into each child's validity bitmap.
349    ///
350    /// This ensures that positions where the struct itself is null are also
351    /// null in each returned child array. Fields that were non-nullable are
352    /// marked nullable in the returned [`Fields`] when the struct has nulls.
353    ///
354    /// If the struct has no nulls, children and fields are returned as-is.
355    ///
356    /// This mirrors the semantics of C++ Arrow's `StructArray::Flatten`.
357    ///
358    /// # Example
359    ///
360    /// ```
361    /// # use std::sync::Arc;
362    /// # use arrow_array::{Array, ArrayRef, Int32Array, StructArray};
363    /// # use arrow_buffer::{BooleanBuffer, NullBuffer};
364    /// # use arrow_schema::{DataType, Field, Fields};
365    /// let child = Arc::new(Int32Array::from(vec![1, 2, 3])) as ArrayRef;
366    /// let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, false, true]));
367    /// let sa = StructArray::new(
368    ///     Fields::from(vec![Field::new("a", DataType::Int32, false)]),
369    ///     vec![child],
370    ///     Some(struct_nulls),
371    /// );
372    /// let (fields, columns) = sa.flatten();
373    /// assert!(fields[0].is_nullable());
374    /// assert!(columns[0].is_null(1));
375    /// ```
376    pub fn flatten(&self) -> (Fields, Vec<ArrayRef>) {
377        let schema_fields = self.fields();
378
379        let struct_nulls = match &self.nulls {
380            Some(n) => n,
381            None => return (schema_fields.clone(), self.fields.clone()),
382        };
383
384        let new_fields: Fields = schema_fields
385            .iter()
386            .map(|f| {
387                if f.is_nullable() {
388                    Arc::clone(f)
389                } else {
390                    Arc::new(f.as_ref().clone().with_nullable(true))
391                }
392            })
393            .collect::<Vec<_>>()
394            .into();
395
396        let new_columns = self
397            .fields
398            .iter()
399            .map(|child| {
400                let merged = NullBuffer::union(Some(struct_nulls), child.nulls());
401                // SAFETY: We only make the null buffer more restrictive (adding nulls).
402                // All data buffers and child data remain unchanged.
403                let data = child.to_data().into_builder().nulls(merged);
404                make_array(unsafe { data.build_unchecked() })
405            })
406            .collect();
407
408        (new_fields, new_columns)
409    }
410}
411
412impl From<ArrayData> for StructArray {
413    fn from(data: ArrayData) -> Self {
414        let (data_type, len, nulls, offset, _buffers, child_data) = data.into_parts();
415
416        let parent_offset = offset;
417        let parent_len = len;
418
419        let fields = child_data
420            .into_iter()
421            .map(|cd| {
422                if parent_offset != 0 || parent_len != cd.len() {
423                    make_array(cd.slice(parent_offset, parent_len))
424                } else {
425                    make_array(cd)
426                }
427            })
428            .collect();
429
430        Self {
431            len,
432            data_type,
433            nulls,
434            fields,
435        }
436    }
437}
438
439impl From<StructArray> for ArrayData {
440    fn from(array: StructArray) -> Self {
441        let builder = ArrayDataBuilder::new(array.data_type)
442            .len(array.len)
443            .nulls(array.nulls)
444            .child_data(array.fields.iter().map(|x| x.to_data()).collect());
445
446        unsafe { builder.build_unchecked() }
447    }
448}
449
450impl TryFrom<Vec<(&str, ArrayRef)>> for StructArray {
451    type Error = ArrowError;
452
453    /// builds a StructArray from a vector of names and arrays.
454    fn try_from(values: Vec<(&str, ArrayRef)>) -> Result<Self, ArrowError> {
455        let (fields, arrays): (Vec<_>, _) = values
456            .into_iter()
457            .map(|(name, array)| {
458                (
459                    Field::new(name, array.data_type().clone(), array.is_nullable()),
460                    array,
461                )
462            })
463            .unzip();
464
465        StructArray::try_new(fields.into(), arrays, None)
466    }
467}
468
469/// SAFETY: Correctly implements the contract of Arrow Arrays
470unsafe impl Array for StructArray {
471    fn as_any(&self) -> &dyn Any {
472        self
473    }
474
475    fn to_data(&self) -> ArrayData {
476        self.clone().into()
477    }
478
479    fn into_data(self) -> ArrayData {
480        self.into()
481    }
482
483    fn data_type(&self) -> &DataType {
484        &self.data_type
485    }
486
487    fn slice(&self, offset: usize, length: usize) -> ArrayRef {
488        Arc::new(self.slice(offset, length))
489    }
490
491    fn len(&self) -> usize {
492        self.len
493    }
494
495    fn is_empty(&self) -> bool {
496        self.len == 0
497    }
498
499    fn shrink_to_fit(&mut self) {
500        if let Some(nulls) = &mut self.nulls {
501            nulls.shrink_to_fit();
502        }
503        self.fields.iter_mut().for_each(|n| n.shrink_to_fit());
504    }
505
506    fn offset(&self) -> usize {
507        0
508    }
509
510    fn nulls(&self) -> Option<&NullBuffer> {
511        self.nulls.as_ref()
512    }
513
514    fn logical_null_count(&self) -> usize {
515        // More efficient that the default implementation
516        self.null_count()
517    }
518
519    fn get_buffer_memory_size(&self) -> usize {
520        let mut size = self.fields.iter().map(|a| a.get_buffer_memory_size()).sum();
521        if let Some(n) = self.nulls.as_ref() {
522            size += n.buffer().capacity();
523        }
524        size
525    }
526
527    fn get_array_memory_size(&self) -> usize {
528        let mut size = self.fields.iter().map(|a| a.get_array_memory_size()).sum();
529        size += std::mem::size_of::<Self>();
530        if let Some(n) = self.nulls.as_ref() {
531            size += n.buffer().capacity();
532        }
533        size
534    }
535
536    #[cfg(feature = "pool")]
537    fn claim(&self, pool: &dyn arrow_buffer::MemoryPool) {
538        for field in &self.fields {
539            field.claim(pool);
540        }
541        if let Some(nulls) = &self.nulls {
542            nulls.claim(pool);
543        }
544    }
545}
546
547impl From<Vec<(FieldRef, ArrayRef)>> for StructArray {
548    fn from(v: Vec<(FieldRef, ArrayRef)>) -> Self {
549        let (fields, arrays): (Vec<_>, _) = v.into_iter().unzip();
550        StructArray::new(fields.into(), arrays, None)
551    }
552}
553
554impl std::fmt::Debug for StructArray {
555    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
556        writeln!(f, "StructArray")?;
557        writeln!(f, "-- validity:")?;
558        writeln!(f, "[")?;
559        print_long_array(self, f, |_array, _index, f| write!(f, "valid"))?;
560        writeln!(f, "]\n[")?;
561        for (child_index, name) in self.column_names().iter().enumerate() {
562            let column = self.column(child_index);
563            writeln!(
564                f,
565                "-- child {}: \"{}\" ({:?})",
566                child_index,
567                name,
568                column.data_type()
569            )?;
570            std::fmt::Debug::fmt(column, f)?;
571            writeln!(f)?;
572        }
573        write!(f, "]")
574    }
575}
576
577impl From<(Vec<(FieldRef, ArrayRef)>, Buffer)> for StructArray {
578    fn from(pair: (Vec<(FieldRef, ArrayRef)>, Buffer)) -> Self {
579        let len = pair.0.first().map(|x| x.1.len()).unwrap_or_default();
580        let (fields, arrays): (Vec<_>, Vec<_>) = pair.0.into_iter().unzip();
581        let nulls = NullBuffer::new(BooleanBuffer::new(pair.1, 0, len));
582        Self::new(fields.into(), arrays, Some(nulls))
583    }
584}
585
586impl From<RecordBatch> for StructArray {
587    fn from(value: RecordBatch) -> Self {
588        Self {
589            len: value.num_rows(),
590            data_type: DataType::Struct(value.schema().fields().clone()),
591            nulls: None,
592            fields: value.columns().to_vec(),
593        }
594    }
595}
596
597impl Index<&str> for StructArray {
598    type Output = ArrayRef;
599
600    /// Get a reference to a column's array by name.
601    ///
602    /// Note: A schema can currently have duplicate field names, in which case
603    /// the first field will always be selected.
604    /// This issue will be addressed in [ARROW-11178](https://issues.apache.org/jira/browse/ARROW-11178)
605    ///
606    /// # Panics
607    ///
608    /// Panics if the name is not in the schema.
609    fn index(&self, name: &str) -> &Self::Output {
610        self.column_by_name(name).unwrap()
611    }
612}
613
614#[cfg(test)]
615mod tests {
616    use super::*;
617
618    use crate::{BooleanArray, Float32Array, Float64Array, Int32Array, Int64Array, StringArray};
619    use arrow_buffer::ToByteSlice;
620
621    #[test]
622    fn test_struct_array_builder() {
623        let boolean_array = BooleanArray::from(vec![false, false, true, true]);
624        let int_array = Int64Array::from(vec![42, 28, 19, 31]);
625
626        let fields = vec![
627            Field::new("a", DataType::Boolean, false),
628            Field::new("b", DataType::Int64, false),
629        ];
630        let struct_array_data = ArrayData::builder(DataType::Struct(fields.into()))
631            .len(4)
632            .add_child_data(boolean_array.to_data())
633            .add_child_data(int_array.to_data())
634            .build()
635            .unwrap();
636        let struct_array = StructArray::from(struct_array_data);
637
638        assert_eq!(struct_array.column(0).as_ref(), &boolean_array);
639        assert_eq!(struct_array.column(1).as_ref(), &int_array);
640    }
641
642    #[test]
643    fn test_struct_array_from() {
644        let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
645        let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));
646
647        let struct_array = StructArray::from(vec![
648            (
649                Arc::new(Field::new("b", DataType::Boolean, false)),
650                boolean.clone() as ArrayRef,
651            ),
652            (
653                Arc::new(Field::new("c", DataType::Int32, false)),
654                int.clone() as ArrayRef,
655            ),
656        ]);
657        assert_eq!(struct_array.column(0).as_ref(), boolean.as_ref());
658        assert_eq!(struct_array.column(1).as_ref(), int.as_ref());
659        assert_eq!(4, struct_array.len());
660        assert_eq!(0, struct_array.null_count());
661        assert_eq!(0, struct_array.offset());
662    }
663
664    #[test]
665    fn test_struct_array_from_data_with_offset_and_length() {
666        // Various ways to make the struct array:
667        //
668        // [{x: 2}, {x: 3}, None]
669        //
670        // from slicing larger buffers/arrays with offsets and lengths
671        let int_arr = Int32Array::from(vec![1, 2, 3, 4, 5]);
672        let int_field = Field::new("x", DataType::Int32, false);
673        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, true, false]));
674        let int_data = int_arr.to_data();
675        // Case 1: Offset + length, nulls are not sliced
676        let case1 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
677            .len(3)
678            .offset(1)
679            .nulls(Some(struct_nulls))
680            .add_child_data(int_data.clone())
681            .build()
682            .unwrap();
683
684        // Case 2: Offset + length, nulls are sliced
685        let struct_nulls =
686            NullBuffer::new(BooleanBuffer::from(vec![true, true, true, false, true]).slice(1, 3));
687        let case2 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
688            .len(3)
689            .offset(1)
690            .nulls(Some(struct_nulls.clone()))
691            .add_child_data(int_data.clone())
692            .build()
693            .unwrap();
694
695        // Case 3: struct length is smaller than child length but no offset
696        let offset_int_data = int_data.slice(1, 4);
697        let case3 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
698            .len(3)
699            .nulls(Some(struct_nulls))
700            .add_child_data(offset_int_data)
701            .build()
702            .unwrap();
703
704        let expected = StructArray::new(
705            Fields::from(vec![int_field.clone()]),
706            vec![Arc::new(int_arr)],
707            Some(NullBuffer::new(BooleanBuffer::from(vec![
708                true, true, true, false, true,
709            ]))),
710        )
711        .slice(1, 3);
712
713        for case in [case1, case2, case3] {
714            let struct_arr_from_data = StructArray::from(case);
715            assert_eq!(struct_arr_from_data, expected);
716            assert_eq!(struct_arr_from_data.column(0), expected.column(0));
717        }
718    }
719
720    #[test]
721    #[should_panic(expected = "assertion failed: (offset + length) <= self.len()")]
722    fn test_struct_array_from_data_with_offset_and_length_error() {
723        let int_arr = Int32Array::from(vec![1, 2, 3, 4, 5]);
724        let int_field = Field::new("x", DataType::Int32, false);
725        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, true, false]));
726        let int_data = int_arr.to_data();
727        // If parent offset is 3 and len is 3 then child must have 6 items
728        let struct_data =
729            ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
730                .len(3)
731                .offset(3)
732                .nulls(Some(struct_nulls))
733                .add_child_data(int_data)
734                .build()
735                .unwrap();
736        let _ = StructArray::from(struct_data);
737    }
738
739    /// validates that struct can be accessed using `column_name` as index i.e. `struct_array["column_name"]`.
740    #[test]
741    fn test_struct_array_index_access() {
742        let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
743        let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));
744
745        let struct_array = StructArray::from(vec![
746            (
747                Arc::new(Field::new("b", DataType::Boolean, false)),
748                boolean.clone() as ArrayRef,
749            ),
750            (
751                Arc::new(Field::new("c", DataType::Int32, false)),
752                int.clone() as ArrayRef,
753            ),
754        ]);
755        assert_eq!(struct_array["b"].as_ref(), boolean.as_ref());
756        assert_eq!(struct_array["c"].as_ref(), int.as_ref());
757    }
758
759    /// validates that the in-memory representation follows [the spec](https://arrow.apache.org/docs/format/Columnar.html#struct-layout)
760    #[test]
761    fn test_struct_array_from_vec() {
762        let strings: ArrayRef = Arc::new(StringArray::from(vec![
763            Some("joe"),
764            None,
765            None,
766            Some("mark"),
767        ]));
768        let ints: ArrayRef = Arc::new(Int32Array::from(vec![Some(1), Some(2), None, Some(4)]));
769
770        let arr =
771            StructArray::try_from(vec![("f1", strings.clone()), ("f2", ints.clone())]).unwrap();
772
773        let struct_data = arr.into_data();
774        assert_eq!(4, struct_data.len());
775        assert_eq!(0, struct_data.null_count());
776
777        let expected_string_data = ArrayData::builder(DataType::Utf8)
778            .len(4)
779            .null_bit_buffer(Some(Buffer::from(&[9_u8])))
780            .add_buffer(Buffer::from([0, 3, 3, 3, 7].to_byte_slice()))
781            .add_buffer(Buffer::from(b"joemark"))
782            .build()
783            .unwrap();
784
785        let expected_int_data = ArrayData::builder(DataType::Int32)
786            .len(4)
787            .null_bit_buffer(Some(Buffer::from(&[11_u8])))
788            .add_buffer(Buffer::from([1, 2, 0, 4].to_byte_slice()))
789            .build()
790            .unwrap();
791
792        assert_eq!(expected_string_data, struct_data.child_data()[0]);
793        assert_eq!(expected_int_data, struct_data.child_data()[1]);
794    }
795
796    #[test]
797    fn test_struct_array_from_vec_error() {
798        let strings: ArrayRef = Arc::new(StringArray::from(vec![
799            Some("joe"),
800            None,
801            None,
802            // 3 elements, not 4
803        ]));
804        let ints: ArrayRef = Arc::new(Int32Array::from(vec![Some(1), Some(2), None, Some(4)]));
805
806        let err = StructArray::try_from(vec![("f1", strings.clone()), ("f2", ints.clone())])
807            .unwrap_err()
808            .to_string();
809
810        assert_eq!(
811            err,
812            "Invalid argument error: Incorrect array length for StructArray field \"f2\", expected 3 got 4"
813        )
814    }
815
816    #[test]
817    #[should_panic(
818        expected = "Incorrect datatype for StructArray field \\\"b\\\", expected Int16 got Boolean"
819    )]
820    fn test_struct_array_from_mismatched_types_single() {
821        drop(StructArray::from(vec![(
822            Arc::new(Field::new("b", DataType::Int16, false)),
823            Arc::new(BooleanArray::from(vec![false, false, true, true])) as Arc<dyn Array>,
824        )]));
825    }
826
827    #[test]
828    #[should_panic(
829        expected = "Incorrect datatype for StructArray field \\\"b\\\", expected Int16 got Boolean"
830    )]
831    fn test_struct_array_from_mismatched_types_multiple() {
832        drop(StructArray::from(vec![
833            (
834                Arc::new(Field::new("b", DataType::Int16, false)),
835                Arc::new(BooleanArray::from(vec![false, false, true, true])) as Arc<dyn Array>,
836            ),
837            (
838                Arc::new(Field::new("c", DataType::Utf8, false)),
839                Arc::new(Int32Array::from(vec![42, 28, 19, 31])),
840            ),
841        ]));
842    }
843
844    #[test]
845    fn test_struct_array_slice() {
846        let boolean_data = ArrayData::builder(DataType::Boolean)
847            .len(5)
848            .add_buffer(Buffer::from([0b00010000]))
849            .null_bit_buffer(Some(Buffer::from([0b00010001])))
850            .build()
851            .unwrap();
852        let int_data = ArrayData::builder(DataType::Int32)
853            .len(5)
854            .add_buffer(Buffer::from([0, 28, 42, 0, 0].to_byte_slice()))
855            .null_bit_buffer(Some(Buffer::from([0b00000110])))
856            .build()
857            .unwrap();
858
859        let field_types = vec![
860            Field::new("a", DataType::Boolean, true),
861            Field::new("b", DataType::Int32, true),
862        ];
863        let struct_array_data = ArrayData::builder(DataType::Struct(field_types.into()))
864            .len(5)
865            .add_child_data(boolean_data.clone())
866            .add_child_data(int_data.clone())
867            .null_bit_buffer(Some(Buffer::from([0b00010111])))
868            .build()
869            .unwrap();
870        let struct_array = StructArray::from(struct_array_data);
871
872        assert_eq!(5, struct_array.len());
873        assert_eq!(1, struct_array.null_count());
874        assert!(struct_array.is_valid(0));
875        assert!(struct_array.is_valid(1));
876        assert!(struct_array.is_valid(2));
877        assert!(struct_array.is_null(3));
878        assert!(struct_array.is_valid(4));
879        assert_eq!(boolean_data, struct_array.column(0).to_data());
880        assert_eq!(int_data, struct_array.column(1).to_data());
881
882        let c0 = struct_array.column(0);
883        let c0 = c0.as_any().downcast_ref::<BooleanArray>().unwrap();
884        assert_eq!(5, c0.len());
885        assert_eq!(3, c0.null_count());
886        assert!(c0.is_valid(0));
887        assert!(!c0.value(0));
888        assert!(c0.is_null(1));
889        assert!(c0.is_null(2));
890        assert!(c0.is_null(3));
891        assert!(c0.is_valid(4));
892        assert!(c0.value(4));
893
894        let c1 = struct_array.column(1);
895        let c1 = c1.as_any().downcast_ref::<Int32Array>().unwrap();
896        assert_eq!(5, c1.len());
897        assert_eq!(3, c1.null_count());
898        assert!(c1.is_null(0));
899        assert!(c1.is_valid(1));
900        assert_eq!(28, c1.value(1));
901        assert!(c1.is_valid(2));
902        assert_eq!(42, c1.value(2));
903        assert!(c1.is_null(3));
904        assert!(c1.is_null(4));
905
906        let sliced_array = struct_array.slice(2, 3);
907        let sliced_array = sliced_array.as_any().downcast_ref::<StructArray>().unwrap();
908        assert_eq!(3, sliced_array.len());
909        assert_eq!(1, sliced_array.null_count());
910        assert!(sliced_array.is_valid(0));
911        assert!(sliced_array.is_null(1));
912        assert!(sliced_array.is_valid(2));
913
914        let sliced_c0 = sliced_array.column(0);
915        let sliced_c0 = sliced_c0.as_any().downcast_ref::<BooleanArray>().unwrap();
916        assert_eq!(3, sliced_c0.len());
917        assert!(sliced_c0.is_null(0));
918        assert!(sliced_c0.is_null(1));
919        assert!(sliced_c0.is_valid(2));
920        assert!(sliced_c0.value(2));
921
922        let sliced_c1 = sliced_array.column(1);
923        let sliced_c1 = sliced_c1.as_any().downcast_ref::<Int32Array>().unwrap();
924        assert_eq!(3, sliced_c1.len());
925        assert!(sliced_c1.is_valid(0));
926        assert_eq!(42, sliced_c1.value(0));
927        assert!(sliced_c1.is_null(1));
928        assert!(sliced_c1.is_null(2));
929    }
930
931    #[test]
932    #[should_panic(
933        expected = "Incorrect array length for StructArray field \\\"c\\\", expected 1 got 2"
934    )]
935    fn test_invalid_struct_child_array_lengths() {
936        drop(StructArray::from(vec![
937            (
938                Arc::new(Field::new("b", DataType::Float32, false)),
939                Arc::new(Float32Array::from(vec![1.1])) as Arc<dyn Array>,
940            ),
941            (
942                Arc::new(Field::new("c", DataType::Float64, false)),
943                Arc::new(Float64Array::from(vec![2.2, 3.3])),
944            ),
945        ]));
946    }
947
948    #[test]
949    #[should_panic(expected = "use StructArray::try_new_with_length")]
950    fn test_struct_array_from_empty() {
951        // This can't work because we don't know how many rows the array should have.  Previously we inferred 0 but
952        // that often led to bugs.
953        let _ = StructArray::from(vec![]);
954    }
955
956    #[test]
957    fn test_empty_struct_array() {
958        assert!(StructArray::try_new(Fields::empty(), vec![], None).is_err());
959
960        let arr = StructArray::new_empty_fields(10, None);
961        assert_eq!(arr.len(), 10);
962        assert_eq!(arr.null_count(), 0);
963        assert_eq!(arr.num_columns(), 0);
964
965        let arr2 = StructArray::try_new_with_length(Fields::empty(), vec![], None, 10).unwrap();
966        assert_eq!(arr2.len(), 10);
967
968        let arr = StructArray::new_empty_fields(10, Some(NullBuffer::new_null(10)));
969        assert_eq!(arr.len(), 10);
970        assert_eq!(arr.null_count(), 10);
971        assert_eq!(arr.num_columns(), 0);
972
973        let arr2 = StructArray::try_new_with_length(
974            Fields::empty(),
975            vec![],
976            Some(NullBuffer::new_null(10)),
977            10,
978        )
979        .unwrap();
980        assert_eq!(arr2.len(), 10);
981    }
982
983    #[test]
984    #[should_panic(expected = "Found unmasked nulls for non-nullable StructArray field \\\"c\\\"")]
985    fn test_struct_array_from_mismatched_nullability() {
986        drop(StructArray::from(vec![(
987            Arc::new(Field::new("c", DataType::Int32, false)),
988            Arc::new(Int32Array::from(vec![Some(42), None, Some(19)])) as ArrayRef,
989        )]));
990    }
991
992    #[test]
993    fn test_struct_array_fmt_debug() {
994        let arr: StructArray = StructArray::new(
995            vec![Arc::new(Field::new("c", DataType::Int32, true))].into(),
996            vec![Arc::new(Int32Array::from((0..30).collect::<Vec<_>>())) as ArrayRef],
997            Some(NullBuffer::new(BooleanBuffer::from(
998                (0..30).map(|i| i % 2 == 0).collect::<Vec<_>>(),
999            ))),
1000        );
1001        assert_eq!(
1002            format!("{arr:?}"),
1003            "StructArray\n-- validity:\n[\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n  ...10 elements...,\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n  valid,\n  null,\n]\n[\n-- child 0: \"c\" (Int32)\nPrimitiveArray<Int32>\n[\n  0,\n  1,\n  2,\n  3,\n  4,\n  5,\n  6,\n  7,\n  8,\n  9,\n  ...10 elements...,\n  20,\n  21,\n  22,\n  23,\n  24,\n  25,\n  26,\n  27,\n  28,\n  29,\n]\n]"
1004        )
1005    }
1006
1007    #[test]
1008    fn test_struct_array_logical_nulls() {
1009        // Field is non-nullable
1010        let field = Field::new("a", DataType::Int32, false);
1011        let values = vec![1, 2, 3];
1012        // Create a NullBuffer with all bits set to valid (true)
1013        let nulls = NullBuffer::from(vec![true, true, true]);
1014        let array = Int32Array::new(values.into(), Some(nulls));
1015        let child = Arc::new(array) as ArrayRef;
1016        assert!(child.logical_nulls().is_some());
1017        assert_eq!(child.logical_nulls().unwrap().null_count(), 0);
1018
1019        let fields = Fields::from(vec![field]);
1020        let arrays = vec![child];
1021        let nulls = None;
1022
1023        StructArray::try_new(fields, arrays, nulls).expect("should not error");
1024    }
1025
1026    #[test]
1027    fn test_flatten_no_nulls() {
1028        let child = Arc::new(Int32Array::from(vec![1, 2, 3])) as ArrayRef;
1029        let sa = StructArray::from(vec![(
1030            Arc::new(Field::new("a", DataType::Int32, false)),
1031            child,
1032        )]);
1033
1034        let (fields, columns) = sa.flatten();
1035
1036        assert_eq!(columns.len(), 1);
1037        assert!(!fields[0].is_nullable());
1038        assert_eq!(columns[0].null_count(), 0);
1039        assert_eq!(columns[0].len(), 3);
1040    }
1041
1042    #[test]
1043    fn test_flatten_struct_nulls_child_no_nulls() {
1044        let child = Arc::new(Int32Array::from(vec![1, 2, 3])) as ArrayRef;
1045        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, false, true]));
1046        let sa = StructArray::new(
1047            Fields::from(vec![Field::new("a", DataType::Int32, false)]),
1048            vec![child],
1049            Some(struct_nulls),
1050        );
1051
1052        let (fields, columns) = sa.flatten();
1053
1054        assert!(fields[0].is_nullable());
1055        assert!(columns[0].is_valid(0));
1056        assert!(columns[0].is_null(1));
1057        assert!(columns[0].is_valid(2));
1058        assert_eq!(columns[0].null_count(), 1);
1059    }
1060
1061    #[test]
1062    fn test_flatten_both_have_nulls() {
1063        // struct validity: [valid, null,  valid, valid]
1064        // child validity:  [valid, valid, null,  valid]
1065        // expected:        [valid, null,  null,  valid]
1066        let child = Arc::new(Int32Array::from(vec![Some(1), Some(2), None, Some(4)])) as ArrayRef;
1067        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, false, true, true]));
1068        let sa = StructArray::new(
1069            Fields::from(vec![Field::new("a", DataType::Int32, true)]),
1070            vec![child],
1071            Some(struct_nulls),
1072        );
1073
1074        let (fields, columns) = sa.flatten();
1075
1076        assert!(fields[0].is_nullable());
1077        assert!(columns[0].is_valid(0));
1078        assert!(columns[0].is_null(1));
1079        assert!(columns[0].is_null(2));
1080        assert!(columns[0].is_valid(3));
1081        assert_eq!(columns[0].null_count(), 2);
1082    }
1083
1084    #[test]
1085    fn test_flatten_sliced_struct() {
1086        let child = Arc::new(Int32Array::from(vec![1, 2, 3, 4])) as ArrayRef;
1087        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, false, true, false]));
1088        let sa = StructArray::new(
1089            Fields::from(vec![Field::new("a", DataType::Int32, false)]),
1090            vec![child],
1091            Some(struct_nulls),
1092        );
1093        let sliced = sa.slice(1, 2);
1094
1095        let (fields, columns) = sliced.flatten();
1096
1097        assert!(fields[0].is_nullable());
1098        assert_eq!(columns[0].len(), 2);
1099        assert!(columns[0].is_null(0));
1100        assert!(columns[0].is_valid(1));
1101    }
1102
1103    #[test]
1104    fn test_flatten_multiple_children() {
1105        let int_child = Arc::new(Int32Array::from(vec![Some(1), Some(2), None])) as ArrayRef;
1106        let str_child = Arc::new(StringArray::from(vec![Some("a"), None, Some("c")])) as ArrayRef;
1107        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, false, true]));
1108        let sa = StructArray::new(
1109            Fields::from(vec![
1110                Field::new("ints", DataType::Int32, true),
1111                Field::new("strs", DataType::Utf8, true),
1112            ]),
1113            vec![int_child, str_child],
1114            Some(struct_nulls),
1115        );
1116
1117        let (fields, columns) = sa.flatten();
1118
1119        assert_eq!(fields.len(), 2);
1120        // int: [valid, null(struct), null(child)] => null_count=2
1121        assert_eq!(columns[0].null_count(), 2);
1122        assert!(columns[0].is_valid(0));
1123        assert!(columns[0].is_null(1));
1124        assert!(columns[0].is_null(2));
1125        // str: [valid, null(struct+child), valid] => null_count=1
1126        assert_eq!(columns[1].null_count(), 1);
1127        assert!(columns[1].is_valid(0));
1128        assert!(columns[1].is_null(1));
1129        assert!(columns[1].is_valid(2));
1130    }
1131
1132    #[test]
1133    fn test_flatten_empty_struct() {
1134        let sa = StructArray::new_empty_fields(5, Some(NullBuffer::new_null(5)));
1135
1136        let (fields, columns) = sa.flatten();
1137
1138        assert_eq!(fields.len(), 0);
1139        assert_eq!(columns.len(), 0);
1140    }
1141
1142    #[test]
1143    fn test_flatten_field_nullability_update() {
1144        let non_null_child = Arc::new(Int32Array::from(vec![1, 2, 3])) as ArrayRef;
1145        let nullable_child = Arc::new(Int32Array::from(vec![Some(1), None, Some(3)])) as ArrayRef;
1146        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, true, false]));
1147        let sa = StructArray::new(
1148            Fields::from(vec![
1149                Field::new("non_null", DataType::Int32, false),
1150                Field::new("nullable", DataType::Int32, true),
1151            ]),
1152            vec![non_null_child, nullable_child],
1153            Some(struct_nulls),
1154        );
1155
1156        let (fields, _columns) = sa.flatten();
1157
1158        assert!(fields[0].is_nullable()); // was false, now true
1159        assert!(fields[1].is_nullable()); // was true, stays true
1160    }
1161}
arrow_array/array/struct_array.rs

arrow_array/array/
struct_array.rs
