[Qgis-user] Write vector attribute table from pandas dataframe

[ming han]

Thanks, Wouter and Nicolas

    I will give it a try.

Cheers
Ming

On Sun, Apr 24, 2022 at 9:33 AM Wouter Impens via Qgis-user <
qgis-user at lists.osgeo.org> wrote:

> Hi,
>
> If you have a field to join on, you could export the dataframe to
> something that is readable in QGIS like csv or xlsx
>
> Greetings
> Wouter
>
> Op za 23 apr. 2022 om 19:34 schreef Nicolas Cadieux via Qgis-user <
> qgis-user at lists.osgeo.org>:
>
>> Hi Ming,
>>
>> The best thing would be to show your code and ask others how it can be
>> optimized.  I find that https://gis.stackexchange.com/ is the best place
>> to do this but this user list definitely has some very  competent
>> programmers.  Not being one of those competent programmers, I will just
>> state that pandas and geopandas use a process called vectorization where
>> the “for loop” is done for you.
>>
>>
>> https://medium.com/analytics-vidhya/understanding-vectorization-in-numpy-and-pandas-188b6ebc5398
>>
>> This means that looping over elements in a dataframe can be MUCH slower
>> than using vectorization.  So basically, you need to figure out the right
>> code and avoid “for loops“ when using dataframes.
>>
>> Hope this helps
>>
>> Nicolas Cadieux
>> https://gitlab.com/njacadieux
>>
>> Le 22 avr. 2022 à 11:50, ming han via Qgis-user <
>> qgis-user at lists.osgeo.org> a écrit :
>>
>> 
>> Hi everyone
>>
>>      Is there an efficient way to copy data in a pandas dataframe to the
>> vector attribute table?
>>
>>       I am looping element by element, which is very slow.
>>
>> Thanks
>> Ming
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