wi1 = {
"name" : "Clean room A",
"prev" : None,
"next" : None
}
wi2 = {
"name" : "Clean room B",
"prev" : None,
"next" : None
}
wi3 = {
"name" : "Clean room C",
"prev" : None,
"next" : None
}
def add_item_begin(my_collection, new_item):
new_item["next"] = my_collection
new_item["prev"] = None
if my_collection:
my_collection["prev"] = new_item
my_collection = new_item
return my_collection
def add_item_end(my_collection, new_item): if my_collection == None: my_collection = new_item new_item["next"] = None new_item["prev"] = None return my_collection else: item = my_collection while item["next"]: item = item["next"] item["next"] = new_item new_item["next"] = None new_item["prev"] = item return my_collection
work = None work = add_item_end(work, wi1) work = add_item_end(work, wi2) work = add_item_end(work, wi3) item = work while item: print(item["name"]) item = item["next"]
def del_item_begin(my_collection): # item is the element that should be removed item = my_collection # execute only if the collection was not empty if item: # my collection should point to the next element my_collection = item['next'] # if the collection is not empty, it's first element property 'prev' should point to None if my_collection: my_collection['prev'] = None return my_collection, item
return my_collection, item
work, item = del_item_begin(work)
item['name']
work
wi4 = {
"name" : "Clean room D",
"prev" : None,
"next" : None
}
work = add_item_end(work, wi4)
item = work
while item:
print(item["name"])
item = item["next"]
work, item = del_item_begin(work)
item['name']
item = work
while item:
print(item["name"])
item = item["next"]
wi5 = {
"name" : "Clean room E",
"prev" : None,
"next" : None
}
work = add_item_begin(work, wi5)
work, item = del_item_begin(work)
item['name']
list_fifo = []
list_fifo.append("Plant a tree")
list_fifo.append("Build a house")
list_fifo.append("Have a son")
print(list_fifo)
while len(list_fifo) > 0:
task = list_fifo.pop(0)
print(task)
list_lifo = []
list_lifo.append('Blue Box with Glass')
list_lifo.append('Bag with Presents')
list_lifo.append('Barrel of Beer')
list_lifo.append('Cage with a Tiger')
print(list_lifo)
while len(list_lifo) > 0:
task = list_lifo.pop()
print(task)