# Python list to csharp list

**URL:** <https://forum.dynamobim.com/t/python-list-to-csharp-list/73835>\
**Category:** Lists-Logic\
**Tags:** revit, dynamo\
**Created:** [March 1, 2022, 4:41pm UTC](https://forum.dynamobim.com/t/python-list-to-csharp-list/73835 "2022-03-01T16:41:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![CHANDU](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/chandu/32/169017_2.png) [@CHANDU](https://forum.dynamobim.com/u/CHANDU)\
**Post date:** [March 1, 2022, 4:41pm UTC](https://forum.dynamobim.com/t/python-list-to-csharp-list/73835/1 "2022-03-01T16:41:41Z")

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Hi Everyone…I have got a python list of Revit curves in a nested list which I want to add to a csharp list where the data type is a curve but I am getting an error. Can anyone suggest me on doing this…I have attached the images for reference. Thanks in advance…!!

 ![revit list](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/7/c/7c5df234db2867ad64bb2b9e372eb75f789dc223.png)  
 ![csharp list](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/a/0aafce97fa21f350956804339ecd398cc1867594.png)

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<div class="post-metadata">

**Author:** ![Elie.Trad](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/elie.trad/32/110373_2.png) [@Elie.Trad](https://forum.dynamobim.com/u/Elie.Trad)\
**Post date:** [March 1, 2022, 7:28pm UTC](https://forum.dynamobim.com/t/python-list-to-csharp-list/73835/2 "2022-03-01T19:28:46Z")

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@CHANDU I think you need to loop over the nested lists as well

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<div class="post-metadata">

**Author:** ![c.poupin](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/c.poupin/32/89152_2.png) [@c.poupin](https://forum.dynamobim.com/u/c.poupin)\
**Post date:** [March 1, 2022, 7:32pm UTC](https://forum.dynamobim.com/t/python-list-to-csharp-list/73835/3 "2022-03-01T19:32:11Z")

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Here an example

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/3/0/30fe6a34dd9823149a37e656c36b7448cf3dff84.png)

```auto
import clr
import sys
import System
clr.AddReference('ProtoGeometry')
from Autodesk.DesignScript.Geometry import *
import Autodesk.DesignScript.Geometry as DS

#import Revit API
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
import Autodesk.Revit.DB as DB

#import net library
from System.Collections.Generic import List

clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)
clr.ImportExtensions(Revit.Elements)

#import transactionManager and DocumentManager (RevitServices is specific to Dynamo)
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
doc = DocumentManager.Instance.CurrentDBDocument

#Preparing input from dynamo to revit
lstcurves = UnwrapElement(IN[0])

net_Lst = List[List[DB.Curve]]()
for sublst in lstcurves:
	lst = List[DB.Curve]([x.ToRevitType() for x in sublst])
	net_Lst.Add(lst)
	
OUT = net_Lst

```

_ **it is better to post your code, to facilitate the users who will come to help you** _

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<div class="post-metadata">

**Author:** ![CHANDU](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/chandu/32/169017_2.png) [@CHANDU](https://forum.dynamobim.com/u/CHANDU)\
**Post date:** [March 3, 2022, 2:34pm UTC](https://forum.dynamobim.com/t/python-list-to-csharp-list/73835/4 "2022-03-03T14:34:25Z")

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Thanks a lot…!! It worked for me…