How to make a lacing in Python Script

Developers
12

What is being described it seems is carrying out a for loop within a for loop. I agree with @Nick_Boyts, this could be easily achieved by changing the lacing of the node being input.

But in python terms to access a nested list (this is assuming a 2 level list) would be :

for i in items: 
   for j in i: 
       do_something()

this is saying for each item in the top list [i] … then for every item within this list [j]…

think…

i[0],j[0]
i[0],j[1]
i[1],j[0]
i[1],j[1]
i[2],j[0]
i[2],j[1]

This will only work for a two-level list, if you want to access the most nested items you would need to look into a recursive function which tests for list lengths until you are down to single items.

Without looking too much into the code … from a brief glance it seems you would want to change

ids = list()
rejects = list()
for item in items:
    try:
	    ids.append(item.Id)
    except:
	    rejects.append(item)
items = List[ElementId](ids)

to

ids = [] # this is shorthand for a list 
rejects = []
for sub_list in items: # this will iterate through the top list
    for item in sub_list: # this will iterate through all items within the top lists 
        try:
	        ids.append(item.Id)
        except:
	        rejects.append(item)
items = List[ElementId](ids)

Hope this helps / makes sense

(I’m slightly to dubious as to how good a name sublist is here for a variable, but hopefully it serves to illustrate the point)

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