Category expression syntax ?

Nov 18, 2014 at 9:35 AM
Edited Nov 18, 2014 at 9:36 AM
Hi,

I'm looking for a few documentation about expression syntax inside categories. Is there some function like SUBSTR([fieldname],2,3) to extract part of a field or INSTR to find a string inside another ?

Thanks

Olivier
Coordinator
Nov 23, 2014 at 11:23 AM
Hi Olivier,

I can't help you with this question. I'll ask around. I'll try to add some more explanation to the documentation: http://www.mapwindow.org/documentation/mapwingis4.9/class_shapefile_category.html

I'll keep you posted.

Paul
Developer
Nov 23, 2014 at 1:09 PM
I'm afraid no string functions are provided by core parser at the moment. So I guess the only way to go is to insert a new field, populate it using whatever functions you like, and then generate categories based on it. For the reference on the operators supported by core parser you can look into the source (see CExpression::ReadOperation): https://mapwingis.codeplex.com/SourceControl/latest#MapWinGIS/trunk/Processing/Expression.cpp