[Docs] Wrong about the struct hiding valid children values in the example

[stfdxv]

Describe the bug, including details regarding any error messages, version, and platform.

Valid children values are not hidden by the struct's validity bitmap in the example, but the abstract says they are.
Struct's validity bitmap: 00001011
Field-0's validity bitmap: 00001001
Field-1's validity bitmap: 00001011

Component(s)

Website

[kou]

Hmm. What is the expected validity bitmaps you think?

[stfdxv]

For example.
Struct's validity bitmap: 00001011
Field-0's validity bitmap: 00001101
Field-1's validity bitmap: 00001111
Struct's values: [{'joe', 1}, {null, 2}, null, {'mark', 4}]
Field-0's values: ['joe', null, 'homer', 'mark']
Field-1's values: [1, 2, 3, 4]

If field-0 or field-1 had valid values at index 2 (hence validity bit 1 at index 2), these values - 'homer' and 3 - would be hidden indeed by the struct's validity bit 0 at index 2.

[kou]

Ah, do you focus on the part?

This is illustrated in the example above, the child arrays have valid entries for the null struct but they are “hidden” by the struct array’s validity bitmap. However, when treated independently, corresponding entries of the children array will be non-null.

I see. Could you open a pull request to fix the example validity bitmaps?

[stfdxv]

I'll do it.