#2499: v.in.ogr in does not handle "nan" in attribute tables properly
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Reporter: sbl | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone: 7.8.3
Component: Vector | Version: unspecified
Resolution: | Keywords: v.in.ogr, DBMI, SQLite, nan
CPU: Unspecified | Platform: Unspecified
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Comment (by mmetz):
Replying to [comment:11 sbl]:
> Here is how it was handeled in Pandas:
> https://github.com/pandas-dev/pandas/pull/8208
>
> As a simple example for reproduction (though not with v.net.centrality)
you could do:
>
> {{{
> db.execute sql="CREATE TABLE test (column double precision);"
> db.execute sql="INSERT INTO test VALUES (-nan);"
> # in contrast to
> db.execute sql="INSERT INTO test VALUES (NULL);"
> }}}
>
> SQLite seems to have a workaround:
>
http://system.data.sqlite.org/index.html/tktview/e06c4caff3c433c80616ae5c6df63fc830825e59
> But that does not seem to be available in default packages of SQLite and
other DBMIs seem to struggle With nan/NaN as well… So, this does not seem
to be trivial...
The SQLite workaround with !GetAllAsText seems ugly. What works is
{{{
db.execute sql="INSERT INTO test VALUES ('-nan');"
}}}
but then SQLite converts '-nan' to -0 (zero) which is wrong. Same for
inf/-inf. Using NULL is also not correct, because NULL means "no entry",
whereas nan and inf are numbers that can be represented as floating point
numbers.
--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2499#comment:12>
GRASS GIS <https://grass.osgeo.org>
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