Hello, I think an empty string array will have an offsets buffer of length 1 with the value 0.
Sasha Krassovsky > 9 мая 2022 г., в 05:23, Yang hao <[email protected]> написал(а): > > For an empty (list, binary, string) array, what should the offsets buffer > be? Empty buffer or a buffer containing a single zero? Or both are valid? > > There is some related information I found: > > 1. In the Apache Arrow Format: > link<https://arrow.apache.org/docs/format/Columnar.html#variable-size-binary-layout> > > The offsets buffer contains length + 1 signed integers (either 32-bit or > 64-bit, depending on the logical type). > Generally the first slot in the offsets array is 0, and the last slot is the > length of the values array. > > 1. A related issue in arrow-rs: > link<https://github.com/apache/arrow-rs/issues/1620> > > We find that some test data in arrow-testing has empty offsets buffer (but > not 100% sure). > > 1. In arrow2 (rust), offsets buffer cannot be empty: > > Link1<https://github.com/jorgecarleitao/arrow2/blob/8fb3b8d3f05cdc3d51f1314cfeb9bec39196789c/src/array/specification.rs#L101> > > Link2<https://github.com/jorgecarleitao/arrow2/blob/main/src/io/ipc/read/array/binary.rs#L45> > > 1. In arrow (c++), (sorry I am not familiar with the c++ implementation): > > Link<https://github.com/apache/arrow/blob/c70426f73326b3852d1bd7c31d98be4743f3fcba/cpp/src/arrow/array/array_nested.cc#L111-L113> > > Looking forward to your opintions! > > > Regards, > Remzi
