[QGIS-Developer] QGIS processing model: extract specific attribute of a single feature to a string

[Andreas Neumann]

Hi Ujaval, 

Thanks for the "hacky" idea ;-) 

I am happy to report that it worked for me. 

For the long run, it would be good to have an algorithm to extract a
string from an attribute of a selected feature (something like
attribute(get_feature(expression_to_get_feature),attribute) ) or at
least an "Expression Executor" that outputs a string. Expressions can do
a lot, but getting a string output from an Expression seems to be
impossible. 

Anyway, I can progress now with the rest of my model. 

Thanks again, 

Andreas 

On 2020-08-11 10:15, Ujaval Gandhi wrote:

> I can think of a slightly hacky way. Use the 'Basic Statistics for Field' algorithm, and since your field will have a single value, use either the Minimum or Maximum value output from it (works for string fields too) as the parameter for another algorithm.
> 
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> On Tue, Aug 11, 2020 at 1:23 PM Andreas Neumann <a.neumann at carto.net> wrote: 
> 
>> Hi, 
>> 
>> In a model I aggregate values to a single feature. Then I would like to extract a specific aggregated attribute to a string so I can use it as the input parameter of another algorithm. 
>> 
>> I fail to find a way to do that. Aggregation works fine, string concatenation as well, but I fail to find a way to extract an attribute of a single feature to a string. 
>> 
>> Any ideas? 
>> 
>> I'm on QGIS 3.10, but if necessary I could also use a newer QGIS version. 
>> 
>> Thanks, 
>> 
>> Andreas _______________________________________________
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