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-2146826246 in win32com.client for empty #N/A cell in Excel

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  -2146826246 in win32com.client for empty #N/A cell in Excel Sven Boden <sven.boden@gmail.com> - 2015-08-16 09:53 -0700
    Re: -2146826246 in win32com.client for empty #N/A cell in Excel Chris Angelico <rosuav@gmail.com> - 2015-08-17 04:41 +1000
    Re: -2146826246 in win32com.client for empty #N/A cell in Excel Laura Creighton <lac@openend.se> - 2015-08-16 21:49 +0200
    Re: -2146826246 in win32com.client for empty #N/A cell in Excel Nobody <nobody@nowhere.invalid> - 2015-08-16 22:37 +0100
    Re: -2146826246 in win32com.client for empty #N/A cell in Excel random832@fastmail.us - 2015-08-16 17:39 -0400

#95402 — -2146826246 in win32com.client for empty #N/A cell in Excel

Anyone know how to handle "#N/A" in Excel from win32com.client.

I'm extracting data from an Excel file using win32com.client. Everything works fine except for when the value "#N/A" is entered in excel. An empty cell. I assumed I do something as 

if ws.Cells(r, c).Value is None:
    ...

But that doesn't seem to work. When I debug the piece of code while handling #N/A in a cell the type of the cell according to win32com.client is int and the value in the cell is -2146826246. Chances are small just this number will appear in Excel, but it looks dirty to depend on that value to decide if a cell is empty. Looked around the net for a solution, but nothing came up so far.

Anyone knows how to handle a "#N/A" cell in Excel in the proper way?

Regards,
Sven

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#95406

On Mon, Aug 17, 2015 at 3:27 AM, Albert-Jan Roskam
<sjeik_appie@hotmail.com> wrote:
> Does that number happen to be -1 * sys.maxint?

No, it's -1 * 0x7ff5f806. As a signed 32-bit integer, it's 0x800a07fa.
Does either of those numbers mean anything?

Sven, you might do better to ask on a dedicated Python + Win32 mailing
list; I haven't used Python on Windows much for a while.

ChrisA

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#95413

For what it's worth, I use xlrd for this.  http://www.python-excel.org/

Laura

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#95416

On Sun, 16 Aug 2015 09:53:32 -0700, Sven Boden wrote:

> Anyone knows how to handle a "#N/A" cell in Excel in the proper way?

0x800A07FA is how xlErrNA (error 2042) is marshalled. This isn't specific
to Python; you'll get the same value using e.g C# or VB.NET.

There's a fairly thorough article on this topic at:

https://xldennis.wordpress.com/2006/11/22/
https://xldennis.wordpress.com/2006/11/29/

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#95417

On Sun, Aug 16, 2015, at 14:41, Chris Angelico wrote:
> On Mon, Aug 17, 2015 at 3:27 AM, Albert-Jan Roskam
> <sjeik_appie@hotmail.com> wrote:
> > Does that number happen to be -1 * sys.maxint?
> 
> No, it's -1 * 0x7ff5f806. As a signed 32-bit integer, it's 0x800a07fa.
> Does either of those numbers mean anything?

That's a COM error code, for Excel error 2042, which (unsurprisingly)
means N/A.

http://stackoverflow.com/questions/7526640/any-ideas-why-excel-interop-reads-many-decimals-as-2146826246

Here's some information from someone having the same problem in .NET,
which may or may not be helpful

https://xldennis.wordpress.com/2006/11/22/dealing-with-cverr-values-in-net-%E2%80%93-part-i-the-problem/

It looks like the values are actually returned as a VT_ERROR variant,
which .NET (and apparently python) reads as an integer.

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