I have problem with ghpython. help me please.

Hi. Thank you

I wanna sorting lines through its angle. So, I used dictionary in python, and tried to make bundles consisted of curves which have same angle.

But, my ghpython showed a error message

"Runtime error (MissingMemberException): 'NoneType' object has no attribute 'append'"

I don't know how I fix it, and even I don't know what this message means. please help me.

Attachments:

sorting lines.3dm, 196 KB
sorting crvs.gh, 5 KB

Replies to This Discussion

Permalink Reply by Alik Sumin on August 1, 2016 at 3:32am

you have an error because line 25 is incorrect, you need use
dic_crvs[angs[i]].append(crvs[i])
instead
dic_crvs[angs[i]] = dic_crvs[angs[i]].append(crvs[i]
but you also need change the logic of your code, because when you use set, you change the order of elements in list (set doesn't have an order), therefore angles and curves in lists not corresponding with each other.

Permalink Reply by Jaga on August 1, 2016 at 9:07am

wow.. Thank you! it works.

So, if you okay, could you teach me why "dic_crvs[angs[i]] = dic_crvs[angs[i]].append(crvs[i])" is a wrong sentence?

Permalink Reply by Alik Sumin on August 1, 2016 at 10:03am

because "dic_crvs[angs[i]]" is a key of dictionary and when you write "dict[key]=..." it's mean that u want change a value for this key, not add new item to list. for example:
dict = {a:[1,2], b:[]}
dict[a] = [3]

your dict will be {a:[3], b:[]}

besides dic_crvs[angs[i]].append(crvs[i]) is not an item, if you print this, you will see "None", because it's like an action.

Permalink Reply by Jaga on August 5, 2016 at 1:35am

Thank you! I understand :-)

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