arrow_array/array/
struct_array.rs

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2// or more contributor license agreements.  See the NOTICE file
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4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
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8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
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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::{make_array, new_null_array, Array, ArrayRef, RecordBatch};
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 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
348impl From<ArrayData> for StructArray {
349    fn from(data: ArrayData) -> Self {
350        let parent_offset = data.offset();
351        let parent_len = data.len();
352
353        let fields = data
354            .child_data()
355            .iter()
356            .map(|cd| {
357                if parent_offset != 0 || parent_len != cd.len() {
358                    make_array(cd.slice(parent_offset, parent_len))
359                } else {
360                    make_array(cd.clone())
361                }
362            })
363            .collect();
364
365        Self {
366            len: data.len(),
367            data_type: data.data_type().clone(),
368            nulls: data.nulls().cloned(),
369            fields,
370        }
371    }
372}
373
374impl From<StructArray> for ArrayData {
375    fn from(array: StructArray) -> Self {
376        let builder = ArrayDataBuilder::new(array.data_type)
377            .len(array.len)
378            .nulls(array.nulls)
379            .child_data(array.fields.iter().map(|x| x.to_data()).collect());
380
381        unsafe { builder.build_unchecked() }
382    }
383}
384
385impl TryFrom<Vec<(&str, ArrayRef)>> for StructArray {
386    type Error = ArrowError;
387
388    /// builds a StructArray from a vector of names and arrays.
389    fn try_from(values: Vec<(&str, ArrayRef)>) -> Result<Self, ArrowError> {
390        let (fields, arrays): (Vec<_>, _) = values
391            .into_iter()
392            .map(|(name, array)| {
393                (
394                    Field::new(name, array.data_type().clone(), array.is_nullable()),
395                    array,
396                )
397            })
398            .unzip();
399
400        StructArray::try_new(fields.into(), arrays, None)
401    }
402}
403
404impl Array for StructArray {
405    fn as_any(&self) -> &dyn Any {
406        self
407    }
408
409    fn to_data(&self) -> ArrayData {
410        self.clone().into()
411    }
412
413    fn into_data(self) -> ArrayData {
414        self.into()
415    }
416
417    fn data_type(&self) -> &DataType {
418        &self.data_type
419    }
420
421    fn slice(&self, offset: usize, length: usize) -> ArrayRef {
422        Arc::new(self.slice(offset, length))
423    }
424
425    fn len(&self) -> usize {
426        self.len
427    }
428
429    fn is_empty(&self) -> bool {
430        self.len == 0
431    }
432
433    fn shrink_to_fit(&mut self) {
434        if let Some(nulls) = &mut self.nulls {
435            nulls.shrink_to_fit();
436        }
437        self.fields.iter_mut().for_each(|n| n.shrink_to_fit());
438    }
439
440    fn offset(&self) -> usize {
441        0
442    }
443
444    fn nulls(&self) -> Option<&NullBuffer> {
445        self.nulls.as_ref()
446    }
447
448    fn logical_null_count(&self) -> usize {
449        // More efficient that the default implementation
450        self.null_count()
451    }
452
453    fn get_buffer_memory_size(&self) -> usize {
454        let mut size = self.fields.iter().map(|a| a.get_buffer_memory_size()).sum();
455        if let Some(n) = self.nulls.as_ref() {
456            size += n.buffer().capacity();
457        }
458        size
459    }
460
461    fn get_array_memory_size(&self) -> usize {
462        let mut size = self.fields.iter().map(|a| a.get_array_memory_size()).sum();
463        size += std::mem::size_of::<Self>();
464        if let Some(n) = self.nulls.as_ref() {
465            size += n.buffer().capacity();
466        }
467        size
468    }
469}
470
471impl From<Vec<(FieldRef, ArrayRef)>> for StructArray {
472    fn from(v: Vec<(FieldRef, ArrayRef)>) -> Self {
473        let (fields, arrays): (Vec<_>, _) = v.into_iter().unzip();
474        StructArray::new(fields.into(), arrays, None)
475    }
476}
477
478impl std::fmt::Debug for StructArray {
479    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
480        writeln!(f, "StructArray")?;
481        writeln!(f, "-- validity:")?;
482        writeln!(f, "[")?;
483        print_long_array(self, f, |_array, _index, f| write!(f, "valid"))?;
484        writeln!(f, "]\n[")?;
485        for (child_index, name) in self.column_names().iter().enumerate() {
486            let column = self.column(child_index);
487            writeln!(
488                f,
489                "-- child {}: \"{}\" ({:?})",
490                child_index,
491                name,
492                column.data_type()
493            )?;
494            std::fmt::Debug::fmt(column, f)?;
495            writeln!(f)?;
496        }
497        write!(f, "]")
498    }
499}
500
501impl From<(Vec<(FieldRef, ArrayRef)>, Buffer)> for StructArray {
502    fn from(pair: (Vec<(FieldRef, ArrayRef)>, Buffer)) -> Self {
503        let len = pair.0.first().map(|x| x.1.len()).unwrap_or_default();
504        let (fields, arrays): (Vec<_>, Vec<_>) = pair.0.into_iter().unzip();
505        let nulls = NullBuffer::new(BooleanBuffer::new(pair.1, 0, len));
506        Self::new(fields.into(), arrays, Some(nulls))
507    }
508}
509
510impl From<RecordBatch> for StructArray {
511    fn from(value: RecordBatch) -> Self {
512        Self {
513            len: value.num_rows(),
514            data_type: DataType::Struct(value.schema().fields().clone()),
515            nulls: None,
516            fields: value.columns().to_vec(),
517        }
518    }
519}
520
521impl Index<&str> for StructArray {
522    type Output = ArrayRef;
523
524    /// Get a reference to a column's array by name.
525    ///
526    /// Note: A schema can currently have duplicate field names, in which case
527    /// the first field will always be selected.
528    /// This issue will be addressed in [ARROW-11178](https://issues.apache.org/jira/browse/ARROW-11178)
529    ///
530    /// # Panics
531    ///
532    /// Panics if the name is not in the schema.
533    fn index(&self, name: &str) -> &Self::Output {
534        self.column_by_name(name).unwrap()
535    }
536}
537
538#[cfg(test)]
539mod tests {
540    use super::*;
541
542    use crate::{BooleanArray, Float32Array, Float64Array, Int32Array, Int64Array, StringArray};
543    use arrow_buffer::ToByteSlice;
544
545    #[test]
546    fn test_struct_array_builder() {
547        let boolean_array = BooleanArray::from(vec![false, false, true, true]);
548        let int_array = Int64Array::from(vec![42, 28, 19, 31]);
549
550        let fields = vec![
551            Field::new("a", DataType::Boolean, false),
552            Field::new("b", DataType::Int64, false),
553        ];
554        let struct_array_data = ArrayData::builder(DataType::Struct(fields.into()))
555            .len(4)
556            .add_child_data(boolean_array.to_data())
557            .add_child_data(int_array.to_data())
558            .build()
559            .unwrap();
560        let struct_array = StructArray::from(struct_array_data);
561
562        assert_eq!(struct_array.column(0).as_ref(), &boolean_array);
563        assert_eq!(struct_array.column(1).as_ref(), &int_array);
564    }
565
566    #[test]
567    fn test_struct_array_from() {
568        let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
569        let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));
570
571        let struct_array = StructArray::from(vec![
572            (
573                Arc::new(Field::new("b", DataType::Boolean, false)),
574                boolean.clone() as ArrayRef,
575            ),
576            (
577                Arc::new(Field::new("c", DataType::Int32, false)),
578                int.clone() as ArrayRef,
579            ),
580        ]);
581        assert_eq!(struct_array.column(0).as_ref(), boolean.as_ref());
582        assert_eq!(struct_array.column(1).as_ref(), int.as_ref());
583        assert_eq!(4, struct_array.len());
584        assert_eq!(0, struct_array.null_count());
585        assert_eq!(0, struct_array.offset());
586    }
587
588    #[test]
589    fn test_struct_array_from_data_with_offset_and_length() {
590        // Various ways to make the struct array:
591        //
592        // [{x: 2}, {x: 3}, None]
593        //
594        // from slicing larger buffers/arrays with offsets and lengths
595        let int_arr = Int32Array::from(vec![1, 2, 3, 4, 5]);
596        let int_field = Field::new("x", DataType::Int32, false);
597        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, true, false]));
598        let int_data = int_arr.to_data();
599        // Case 1: Offset + length, nulls are not sliced
600        let case1 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
601            .len(3)
602            .offset(1)
603            .nulls(Some(struct_nulls))
604            .add_child_data(int_data.clone())
605            .build()
606            .unwrap();
607
608        // Case 2: Offset + length, nulls are sliced
609        let struct_nulls =
610            NullBuffer::new(BooleanBuffer::from(vec![true, true, true, false, true]).slice(1, 3));
611        let case2 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
612            .len(3)
613            .offset(1)
614            .nulls(Some(struct_nulls.clone()))
615            .add_child_data(int_data.clone())
616            .build()
617            .unwrap();
618
619        // Case 3: struct length is smaller than child length but no offset
620        let offset_int_data = int_data.slice(1, 4);
621        let case3 = ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
622            .len(3)
623            .nulls(Some(struct_nulls))
624            .add_child_data(offset_int_data)
625            .build()
626            .unwrap();
627
628        let expected = StructArray::new(
629            Fields::from(vec![int_field.clone()]),
630            vec![Arc::new(int_arr)],
631            Some(NullBuffer::new(BooleanBuffer::from(vec![
632                true, true, true, false, true,
633            ]))),
634        )
635        .slice(1, 3);
636
637        for case in [case1, case2, case3] {
638            let struct_arr_from_data = StructArray::from(case);
639            assert_eq!(struct_arr_from_data, expected);
640            assert_eq!(struct_arr_from_data.column(0), expected.column(0));
641        }
642    }
643
644    #[test]
645    #[should_panic(expected = "assertion failed: (offset + length) <= self.len()")]
646    fn test_struct_array_from_data_with_offset_and_length_error() {
647        let int_arr = Int32Array::from(vec![1, 2, 3, 4, 5]);
648        let int_field = Field::new("x", DataType::Int32, false);
649        let struct_nulls = NullBuffer::new(BooleanBuffer::from(vec![true, true, false]));
650        let int_data = int_arr.to_data();
651        // If parent offset is 3 and len is 3 then child must have 6 items
652        let struct_data =
653            ArrayData::builder(DataType::Struct(Fields::from(vec![int_field.clone()])))
654                .len(3)
655                .offset(3)
656                .nulls(Some(struct_nulls))
657                .add_child_data(int_data)
658                .build()
659                .unwrap();
660        let _ = StructArray::from(struct_data);
661    }
662
663    /// validates that struct can be accessed using `column_name` as index i.e. `struct_array["column_name"]`.
664    #[test]
665    fn test_struct_array_index_access() {
666        let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
667        let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));
668
669        let struct_array = StructArray::from(vec![
670            (
671                Arc::new(Field::new("b", DataType::Boolean, false)),
672                boolean.clone() as ArrayRef,
673            ),
674            (
675                Arc::new(Field::new("c", DataType::Int32, false)),
676                int.clone() as ArrayRef,
677            ),
678        ]);
679        assert_eq!(struct_array["b"].as_ref(), boolean.as_ref());
680        assert_eq!(struct_array["c"].as_ref(), int.as_ref());
681    }
682
683    /// validates that the in-memory representation follows [the spec](https://arrow.apache.org/docs/format/Columnar.html#struct-layout)
684    #[test]
685    fn test_struct_array_from_vec() {
686        let strings: ArrayRef = Arc::new(StringArray::from(vec![
687            Some("joe"),
688            None,
689            None,
690            Some("mark"),
691        ]));
692        let ints: ArrayRef = Arc::new(Int32Array::from(vec![Some(1), Some(2), None, Some(4)]));
693
694        let arr =
695            StructArray::try_from(vec![("f1", strings.clone()), ("f2", ints.clone())]).unwrap();
696
697        let struct_data = arr.into_data();
698        assert_eq!(4, struct_data.len());
699        assert_eq!(0, struct_data.null_count());
700
701        let expected_string_data = ArrayData::builder(DataType::Utf8)
702            .len(4)
703            .null_bit_buffer(Some(Buffer::from(&[9_u8])))
704            .add_buffer(Buffer::from([0, 3, 3, 3, 7].to_byte_slice()))
705            .add_buffer(Buffer::from(b"joemark"))
706            .build()
707            .unwrap();
708
709        let expected_int_data = ArrayData::builder(DataType::Int32)
710            .len(4)
711            .null_bit_buffer(Some(Buffer::from(&[11_u8])))
712            .add_buffer(Buffer::from([1, 2, 0, 4].to_byte_slice()))
713            .build()
714            .unwrap();
715
716        assert_eq!(expected_string_data, struct_data.child_data()[0]);
717        assert_eq!(expected_int_data, struct_data.child_data()[1]);
718    }
719
720    #[test]
721    fn test_struct_array_from_vec_error() {
722        let strings: ArrayRef = Arc::new(StringArray::from(vec![
723            Some("joe"),
724            None,
725            None,
726            // 3 elements, not 4
727        ]));
728        let ints: ArrayRef = Arc::new(Int32Array::from(vec![Some(1), Some(2), None, Some(4)]));
729
730        let err = StructArray::try_from(vec![("f1", strings.clone()), ("f2", ints.clone())])
731            .unwrap_err()
732            .to_string();
733
734        assert_eq!(
735            err,
736            "Invalid argument error: Incorrect array length for StructArray field \"f2\", expected 3 got 4"
737        )
738    }
739
740    #[test]
741    #[should_panic(
742        expected = "Incorrect datatype for StructArray field \\\"b\\\", expected Int16 got Boolean"
743    )]
744    fn test_struct_array_from_mismatched_types_single() {
745        drop(StructArray::from(vec![(
746            Arc::new(Field::new("b", DataType::Int16, false)),
747            Arc::new(BooleanArray::from(vec![false, false, true, true])) as Arc<dyn Array>,
748        )]));
749    }
750
751    #[test]
752    #[should_panic(
753        expected = "Incorrect datatype for StructArray field \\\"b\\\", expected Int16 got Boolean"
754    )]
755    fn test_struct_array_from_mismatched_types_multiple() {
756        drop(StructArray::from(vec![
757            (
758                Arc::new(Field::new("b", DataType::Int16, false)),
759                Arc::new(BooleanArray::from(vec![false, false, true, true])) as Arc<dyn Array>,
760            ),
761            (
762                Arc::new(Field::new("c", DataType::Utf8, false)),
763                Arc::new(Int32Array::from(vec![42, 28, 19, 31])),
764            ),
765        ]));
766    }
767
768    #[test]
769    fn test_struct_array_slice() {
770        let boolean_data = ArrayData::builder(DataType::Boolean)
771            .len(5)
772            .add_buffer(Buffer::from([0b00010000]))
773            .null_bit_buffer(Some(Buffer::from([0b00010001])))
774            .build()
775            .unwrap();
776        let int_data = ArrayData::builder(DataType::Int32)
777            .len(5)
778            .add_buffer(Buffer::from([0, 28, 42, 0, 0].to_byte_slice()))
779            .null_bit_buffer(Some(Buffer::from([0b00000110])))
780            .build()
781            .unwrap();
782
783        let field_types = vec![
784            Field::new("a", DataType::Boolean, true),
785            Field::new("b", DataType::Int32, true),
786        ];
787        let struct_array_data = ArrayData::builder(DataType::Struct(field_types.into()))
788            .len(5)
789            .add_child_data(boolean_data.clone())
790            .add_child_data(int_data.clone())
791            .null_bit_buffer(Some(Buffer::from([0b00010111])))
792            .build()
793            .unwrap();
794        let struct_array = StructArray::from(struct_array_data);
795
796        assert_eq!(5, struct_array.len());
797        assert_eq!(1, struct_array.null_count());
798        assert!(struct_array.is_valid(0));
799        assert!(struct_array.is_valid(1));
800        assert!(struct_array.is_valid(2));
801        assert!(struct_array.is_null(3));
802        assert!(struct_array.is_valid(4));
803        assert_eq!(boolean_data, struct_array.column(0).to_data());
804        assert_eq!(int_data, struct_array.column(1).to_data());
805
806        let c0 = struct_array.column(0);
807        let c0 = c0.as_any().downcast_ref::<BooleanArray>().unwrap();
808        assert_eq!(5, c0.len());
809        assert_eq!(3, c0.null_count());
810        assert!(c0.is_valid(0));
811        assert!(!c0.value(0));
812        assert!(c0.is_null(1));
813        assert!(c0.is_null(2));
814        assert!(c0.is_null(3));
815        assert!(c0.is_valid(4));
816        assert!(c0.value(4));
817
818        let c1 = struct_array.column(1);
819        let c1 = c1.as_any().downcast_ref::<Int32Array>().unwrap();
820        assert_eq!(5, c1.len());
821        assert_eq!(3, c1.null_count());
822        assert!(c1.is_null(0));
823        assert!(c1.is_valid(1));
824        assert_eq!(28, c1.value(1));
825        assert!(c1.is_valid(2));
826        assert_eq!(42, c1.value(2));
827        assert!(c1.is_null(3));
828        assert!(c1.is_null(4));
829
830        let sliced_array = struct_array.slice(2, 3);
831        let sliced_array = sliced_array.as_any().downcast_ref::<StructArray>().unwrap();
832        assert_eq!(3, sliced_array.len());
833        assert_eq!(1, sliced_array.null_count());
834        assert!(sliced_array.is_valid(0));
835        assert!(sliced_array.is_null(1));
836        assert!(sliced_array.is_valid(2));
837
838        let sliced_c0 = sliced_array.column(0);
839        let sliced_c0 = sliced_c0.as_any().downcast_ref::<BooleanArray>().unwrap();
840        assert_eq!(3, sliced_c0.len());
841        assert!(sliced_c0.is_null(0));
842        assert!(sliced_c0.is_null(1));
843        assert!(sliced_c0.is_valid(2));
844        assert!(sliced_c0.value(2));
845
846        let sliced_c1 = sliced_array.column(1);
847        let sliced_c1 = sliced_c1.as_any().downcast_ref::<Int32Array>().unwrap();
848        assert_eq!(3, sliced_c1.len());
849        assert!(sliced_c1.is_valid(0));
850        assert_eq!(42, sliced_c1.value(0));
851        assert!(sliced_c1.is_null(1));
852        assert!(sliced_c1.is_null(2));
853    }
854
855    #[test]
856    #[should_panic(
857        expected = "Incorrect array length for StructArray field \\\"c\\\", expected 1 got 2"
858    )]
859    fn test_invalid_struct_child_array_lengths() {
860        drop(StructArray::from(vec![
861            (
862                Arc::new(Field::new("b", DataType::Float32, false)),
863                Arc::new(Float32Array::from(vec![1.1])) as Arc<dyn Array>,
864            ),
865            (
866                Arc::new(Field::new("c", DataType::Float64, false)),
867                Arc::new(Float64Array::from(vec![2.2, 3.3])),
868            ),
869        ]));
870    }
871
872    #[test]
873    #[should_panic(expected = "use StructArray::try_new_with_length")]
874    fn test_struct_array_from_empty() {
875        // This can't work because we don't know how many rows the array should have.  Previously we inferred 0 but
876        // that often led to bugs.
877        let _ = StructArray::from(vec![]);
878    }
879
880    #[test]
881    fn test_empty_struct_array() {
882        assert!(StructArray::try_new(Fields::empty(), vec![], None).is_err());
883
884        let arr = StructArray::new_empty_fields(10, None);
885        assert_eq!(arr.len(), 10);
886        assert_eq!(arr.null_count(), 0);
887        assert_eq!(arr.num_columns(), 0);
888
889        let arr2 = StructArray::try_new_with_length(Fields::empty(), vec![], None, 10).unwrap();
890        assert_eq!(arr2.len(), 10);
891
892        let arr = StructArray::new_empty_fields(10, Some(NullBuffer::new_null(10)));
893        assert_eq!(arr.len(), 10);
894        assert_eq!(arr.null_count(), 10);
895        assert_eq!(arr.num_columns(), 0);
896
897        let arr2 = StructArray::try_new_with_length(
898            Fields::empty(),
899            vec![],
900            Some(NullBuffer::new_null(10)),
901            10,
902        )
903        .unwrap();
904        assert_eq!(arr2.len(), 10);
905    }
906
907    #[test]
908    #[should_panic(expected = "Found unmasked nulls for non-nullable StructArray field \\\"c\\\"")]
909    fn test_struct_array_from_mismatched_nullability() {
910        drop(StructArray::from(vec![(
911            Arc::new(Field::new("c", DataType::Int32, false)),
912            Arc::new(Int32Array::from(vec![Some(42), None, Some(19)])) as ArrayRef,
913        )]));
914    }
915
916    #[test]
917    fn test_struct_array_fmt_debug() {
918        let arr: StructArray = StructArray::new(
919            vec![Arc::new(Field::new("c", DataType::Int32, true))].into(),
920            vec![Arc::new(Int32Array::from((0..30).collect::<Vec<_>>())) as ArrayRef],
921            Some(NullBuffer::new(BooleanBuffer::from(
922                (0..30).map(|i| i % 2 == 0).collect::<Vec<_>>(),
923            ))),
924        );
925        assert_eq!(format!("{arr:?}"), "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]")
926    }
927
928    #[test]
929    fn test_struct_array_logical_nulls() {
930        // Field is non-nullable
931        let field = Field::new("a", DataType::Int32, false);
932        let values = vec![1, 2, 3];
933        // Create a NullBuffer with all bits set to valid (true)
934        let nulls = NullBuffer::from(vec![true, true, true]);
935        let array = Int32Array::new(values.into(), Some(nulls));
936        let child = Arc::new(array) as ArrayRef;
937        assert!(child.logical_nulls().is_some());
938        assert_eq!(child.logical_nulls().unwrap().null_count(), 0);
939
940        let fields = Fields::from(vec![field]);
941        let arrays = vec![child];
942        let nulls = None;
943
944        StructArray::try_new(fields, arrays, nulls).expect("should not error");
945    }
946}
arrow_array/array/struct_array.rs

arrow_array/array/
struct_array.rs
