[GitHub] [arrow-rs] sunchao commented on a change in pull request #1426: Add doc example for creating `FixedSizeListArray`

[GitBox <gi...@apache.org>]

sunchao commented on a change in pull request #1426:
URL: https://github.com/apache/arrow-rs/pull/1426#discussion_r824882822



##########
File path: arrow/src/array/array_list.rs
##########
@@ -342,6 +342,46 @@ pub type LargeListArray = GenericListArray<i64>;
 
 /// A list array where each element is a fixed-size sequence of values with the same
 /// type whose maximum length is represented by a i32.
+/// # Example
+///
+/// ```
+///     # use arrow::array::{Array, ArrayData, FixedSizeListArray, Int32Array};
+///     # use arrow::datatypes::{DataType, Field};
+///     # use arrow::buffer::Buffer;
+///     // Construct a value array
+///     let value_data = ArrayData::builder(DataType::Int32)
+///         .len(9)
+///         .add_buffer(Buffer::from_slice_ref(&[0, 1, 2, 3, 4, 5, 6, 7, 8]))
+///         .build()
+///         .unwrap();
+////     // Construct a list array from the above two

Review comment:
       "from above two"?

##########
File path: arrow/src/array/array_list.rs
##########
@@ -342,6 +342,46 @@ pub type LargeListArray = GenericListArray<i64>;
 
 /// A list array where each element is a fixed-size sequence of values with the same
 /// type whose maximum length is represented by a i32.
+/// # Example

Review comment:
       nit: can we add a blank line before?

##########
File path: arrow/src/array/array_list.rs
##########
@@ -342,6 +342,46 @@ pub type LargeListArray = GenericListArray<i64>;
 
 /// A list array where each element is a fixed-size sequence of values with the same
 /// type whose maximum length is represented by a i32.
+/// # Example
+///
+/// ```
+///     # use arrow::array::{Array, ArrayData, FixedSizeListArray, Int32Array};
+///     # use arrow::datatypes::{DataType, Field};
+///     # use arrow::buffer::Buffer;
+///     // Construct a value array
+///     let value_data = ArrayData::builder(DataType::Int32)
+///         .len(9)
+///         .add_buffer(Buffer::from_slice_ref(&[0, 1, 2, 3, 4, 5, 6, 7, 8]))
+///         .build()
+///         .unwrap();
+////     // Construct a list array from the above two
+///     let list_data_type = DataType::FixedSizeList(
+///         Box::new(Field::new("item", DataType::Int32, false)),
+///         3,
+///     );
+///     let list_data = ArrayData::builder(list_data_type.clone())
+///         .len(3)
+///         .add_child_data(value_data.clone())
+///         .build()
+///         .unwrap();
+///     let list_array = FixedSizeListArray::from(list_data);
+///     let values = list_array.values();
+///     assert_eq!(&value_data, values.data());
+///     assert_eq!(DataType::Int32, list_array.value_type());
+///     assert_eq!(3, list_array.len());
+///     assert_eq!(0, list_array.null_count());
+///     assert_eq!(6, list_array.value_offset(2));
+///     assert_eq!(3, list_array.value_length());
+///     assert_eq!(

Review comment:
       maybe it's clearer to compare whole array content here, for instance, checking `list_array.value(1)` is `[0, 1, 2]`, `list_array.value(2)` is `[3, 4, 5]`, etc.




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