[ARROW-10169] [Rust] Nulls should be rendered as "" rather than default value when pretty printing arrays

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: Rust
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/26177
• Assignee: Andrew Lamb
• Reporter: Andrew Lamb
• Created: 03/Oct/20 10:33
• Updated: 11/Jan/23 08:11
• Resolved: 03/Oct/20 21:38

Description

Null values should be printed as "" when pretty printing. However, as of now, null values in primative arrays are rendered as the type's default value .

For example:

    fn test_pretty_format_batches() -> Result<()> {
        // define a schema.
        let schema = Arc::new(Schema::new(vec![
            Field::new("a", DataType::Utf8, true),
            Field::new("b", DataType::Int32, true),
        ]));

        // define data.
        let batch = RecordBatch::try_new(
            schema,
            vec![
                Arc::new(array::StringArray::from(vec![Some("a"), Some("b"), None, Some("d")])),
                Arc::new(array::Int32Array::from(vec![Some(1), None, Some(10), Some(100)])),
            ],
        )?;

        println!(pretty_format_batches(&[batch])?);

        Ok(())
    }

Outputs:

+---+-----+
| a | b   |
+---+-----+
| a | 1   |
| b | 0   |
|   | 10  |
| d | 100 |
+---+-----+

The second row of b should be '', not 0. The third row of a should also be '', which I think t is by accident

Thanks to jhorstmann horstmann for pointing this out on https://github.com/apache/arrow/pull/8331#issuecomment-702964608

Issue Links

• links to: GitHub Pull Request #8332