Passing variables to and between Python - script components

[Philip7 (Philip)]

I’m having trouble passing variables between Python scripts. In my minimal working example, I group variables into a dictionary and pass it on to the next script. However, when it arrives, the datatype has changed to a string.

I attempted to use type hints, but dictionaries are not available. Previously, As a workaround I used the json module to pass the variable as a string through dumps() and reads(), but this method only works if the data is json-serializable, which is not always the case.

Any guidance on how to pass it on properly is much appreciated.

[AndersDeleuran]

Have a look at this old example:

Accessing data from other components

Another simple GHPython solution (i.e. sending arbitrary structured data from one GHPython component to another) is to structure the data in a Python dictionary (i.e. key/value), wrap that in a list/tuple and output that, it’ll pass as an item along the wire, so set the receiving component input parameter to Item Access and No Type Hint and the data will go right through maintaining its structure: [2018-07-25%2012_32_15-Grasshopper%20-%20180725_PassDict_GHPy_] 180725_PassDict_GHPy.gh (3.6 K…

[Philip7 (Philip)]

Nice, this works very well. Am I correct in assuming, that this works independent of the datatype within the tuple?

For curious future readers, passing on the data as:

(dict,)

works.

[AndersDeleuran]

I would assume so. Note that this tuple wrapping hack is used to work around the fact that a “dictionary that is passed as output from a component will be seen as enumerable … This means that only the keys will be resolved” i.e. only the keys are output:

How to access the exported dictionary in ghPython?

Hi guys I’d like to shed some light on this. So that you know why things are working this way. Please keep in mind: besides reasonable Python programmer goals, while using GhPython we are in Grasshopper land and are using all facilities that come from IronPython. So, things to keep in mind: A dictionary that is passed as output from a component will be seen as enumerable and will be enumerated. Grasshopper needs enumerated objects, and GhPython buffers results for Grasshopper when it sees t…

And that one may also structure the data in a class (see the example by Giulio in the first link), which for other cases may be more appropriate (e.g. cases where you’re already working with classes and not dictionaries). Also note that one can pass lists of dicts/classes if one sets the receiving component parameter access to List Access.