Error: Item not in list


I have a strange problem with Ladybug and Honeybee. Sometimes when I open a new grasshopper document, Lb and HB can “fly”, and other time they doesn’t (all the components have the same error then).

The error is “1. Solution exception:list.index(item): item not in list”

I don’t understand from where it comes. Can you help me with this?


Ilona (298 KB)

Hi Ilona,

Thank you for reporting this. I cannot reproduce the problem on my system. Can you connect a panel to the output of components and send me the full text, so I can see in which line the error happens?

Also the output of blsgPrograms is a list and you probably want to select one of them and apply it to your zones. Image below:




You can find enclosed the screen shot. The error for each component when I connect a panel is the same (line 2, in script).

For your information, I use the following software/Plug-in:

Rhino5= 5 SR4

Grasshopper 0.9.0076

EnergyPlus V8.1

Radiance version 4.2

Daysim 4.0

GHPython 0.5.99 (old version:2013-Dec-09 because LB doesn’t work with the new one)

Thanks, tell me if you need other information.


I’m not sure 100% but i think the problem might be caused becouse your old python version. The recommended versin can be downloaded from this link:
Which is fully compatible with LB+HB. Can be interesting to hear why you say it isn’t.

I don’t remember why I use the old one (108 Ko), may be I’ve read it in some comments, but when I use the new one (117 Ko), I have another error message (see print shot).

When I connect a panel to Ladybug_Ladybuf for example, it says “no data collected”.

Please check if this discussion Mostapha put together helps:
He address many gpython issues there. For sure the new version is not the problem.

Hi Ilona, To solve this issue you need to update Rhino (and not Grasshopper).

  • Mostapha

Thanks, i’m going to try with the new one. i hope it works well!