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[Python] How is it possible to use colon to declare an variable?!

1. M by Martin156131 on 7 Oct 2022, edited 7 Oct 2022 #

   so i watched the Python crash course video for Blender recommend from here https://wiki.osarch.org/index.php?title=Start_coding

   And in the video (43 min) he uses colon between noice_scale and FloatProperty

   

   How is that possible in python syntax?

2. T by theoryshaw on 7 Oct 2022 # +2 votes

   not an expert, but i think...

   https://docs.python.org/3/glossary.html#term-variable-annotation

3. C by cvillagrasa on 7 Oct 2022 # +2 votes

   Prior to Blender 2.8, props were assigned with the equal sign, and now are indeed treated as annotations:

   https://wiki.blender.org/wiki/Reference/Release_Notes/2.80/Python_API/Addons#Class_Property_Registration

4. G by Gorgious on 7 Oct 2022 # +4 votes

   This is indeed a python annotation.

   In the context of Blender's python API it is used to dynamically populate the operator instances that are crated at runtime when you click on an operator's button. You can then access these properties as standard members of the operator instance.

   In order for the API to recognize them you have to declare them as annotations. Otherwise they're just plan old python attributes of the main operator class (except the few attributes beginning with bl_).

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