It is common to prototype code in the Python Editor, and you may think to do this when you need write some code for an Expression. Beware, though they look deceptively similar, the full Gaffer API is not available in expressions, and references to plugs behave quite differently.
This sometimes leads to an attempt to call something like parent["Sphere"]["radius"].getValue() in an expression, and an exception like the following :
ERROR [Execution error] Expression1.__execute :"python/Gaffer/PythonExpressionEngine.py", line 88, in execute line 1, in <module> AttributeError: 'float' object has no attribute 'getValue'Continue reading “Expression vs. Python Editor”