Python Lists

Lists

List is a collection of ordered items separated by comma and enclosed within square brackets.

Lists are indexed and allow duplicate items.

EntityList = ["Body", "Face", "Edge"]
print(EntityList[0])

Output
Body

Unlike strings, lists are mutable i.e. possible to change their contents.

EntityList[0] = "Model"

Use len() method to find the number of items in the list.

Add Items

append()

add to end of the list.

EntityList = ["Body", "Face"]
EntityList.append ("Edge")
print (EntityList)

Output
['Body', 'Face', 'Edge']

insert()

add at a specified position.

EntityList = ["Body", "Face"]
EntityList.insert (0, "Model")
print (EntityList)

Output
['Model', 'Body', 'Face']

Remove Items

remove()

removes the specified item.

EntityList = ["Body", "Face", "Edge"]
EntityList.remove ("Face")
print (EntityList)

Output
['Body', 'Edge']

pop()

removes the item with the specified position.

EntityList = ["Body", "Face", "Edge"]
EntityList.pop (1)
print (EntityList)

Output
['Body', 'Edge']

Delete List or Items

EntityList = ["Body", "Face", "Edge"]
del EntityList[1]print (EntityList)
del EntityList

Output['Body', 'Edge']

Accessing index 1 in this list in future will throw an error, which is not in the case when you remove the item by pop(). When you remove an item by pop() only the item is removed and the memory is not deleted.

Clear List

empties the list.

EntityList = ["Body", "Face", "Edge"]
EntityList.clear()
print (EntityList)

Output
[]

Copy List

Copies the items in the list to another list.

copy()

EntityList = ["Body", "Face", "Edge"]
EntityList1 = EntityList.copy()
print (EntityList1)

Output
['Body', 'Face', 'Edge']

list()

EntityList = ["Body", "Face", "Edge"]
EntityList1 = list(EntityList)
print (EntityList1)

Output
['Body', 'Face', 'Edge']

List Traversal

EntityList = ["Body", "Face", "Edge"]
for e in EntityList:
	print(e)

Output
Body
Face
Edge

Check List for an item

EntityList = ["Body", "Face", "Edge"]
if"Face"in EntityList:
	print("Face")

Output
Face

Nested List

Create list containing other lists.

EntityCAD = ["Body", "Face", "Edge"]
EntityFEM = ["Node", "Element"]
EntityList = (EntityCAD, EntityFEM)
print (EntityList)

Output(['Body', 'Face', 'Edge'], ['Node', 'Element'])