Hi Julien,

Thanks for the response. Yes, the context here is c++ and an otherwise flat 
table where each field is intuitively an option type and therefore might be 
null. I'll take a look at the link you sent, but in the meantime is there any 
reason I would need the valid_bits args from WriteBatchSpaced?

-Mike

-----Original Message-----
From: Julien Le Dem [mailto:[email protected]] 
Sent: Monday, May 15, 2017 14:02
To: [email protected]
Subject: Re: representing NA values

Hi Mike,
Is this a C++ question?
Optional in the schema means it can be null/missing. It usually translate into 
the definition level being 0 (null) or 1 (defined) which is also how it is 
represented in an Arrow validity vector.
Definition levels explanation here:
https://urldefense.proofpoint.com/v2/url?u=https-3A__blog.twitter.com_2013_dremel-2Dmade-2Dsimple-2Dwith-2Dparquet&d=DwIBaQ&c=f5Q7ov8zryUUIGT55zpGgw&r=p7uiAfJkXEwbVhZPqB-VxtsgxuGNpO5tGgnMUX3wqrPAIvdxhcKmn9kvZiXDziBQ&m=NNFEsYUgGnQHXAMWu_9a4omzJBkc5l-CtKlUWtzILgc&s=dfPqlmKc5MUdMOdmn22lxpMtf3J3NMcsGMirSWI44aA&e=
 


On Mon, May 15, 2017 at 7:39 AM, Katelman, Michael < 
[email protected]> wrote:

> Hi,
>
> I was wondering if someone could help me understand what  the correct 
> way is to represent and write out NA values using a TypedColumnWriter.
> Basically, what I want to do is, e.g., repeatedly write out batches of 
> doubles where some of them may arbitrarily be None's. It seemed like 
> maybe some combination of OPTIONAL, definition levels, and valid bits 
> might work, but it wasn't exactly clear to me. So, if someone could 
> point me in the right direction I would appreciate it.
>
> -Mike
>
>
>
>
>
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--
Julien





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