[Qgis-user] use rownum operator with field calculator

[Jürgen E. Fischer]

Hi Otto,

On Wed, 03. Aug 2011 at 11:27:12 +0200, Otto Dassau wrote:
> is it possible to automatically add a rownumber with the field calculator
> based on an existing other column? For example based on an alphabetical
> order in another column ?  

Only if you can come up with an expression that produces the number from the
other value.
 
> And what information does the rownum operator currently use to apply ids?
> Creation order?

The order in which the provider returns the features.  So probably no
particular order.

The field calculator currently iterates the layer independently of the
attribute table and increments the $rownum operator for each processed
feature.


Jürgen

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