''' lists.py
    demonstrates some of the features of python lists
'''

from collections import deque
import functools

''' The following lines demonstrtae how a list works in Python and some common
    list functions
'''
list = []	# creates an empty list
print(list)	
list = [10, 14.5, "Spongebob"]	#lists can contain multiple kinds of data
print(list)
list = [x**2 for x in range(0,19)]   ''' A list can be populated using list 
                                         comprehensions, where we generate a
                                         series of numbers uingg a loop, inside
                                         the list notation '''
print(list)

list2 =[10,20,30,40] ; list1 = []
list1.append("Krabby Patty")	# append adds the item to the end of the list
print(list2)

print(list2[3], list2.index(10)) # We can query for a value using the index and
                                 # query for the index using the value

list2 = [x*3 for x in range(0,20)]  #another list comprehension

''' The following lines show how to slide and slice on a list '''
print(list2[3:15])  # prints list elemets 3 through 15
print(list2[14:])   # element 14 until the end
print(list2[:5])    # from the beginning until element 5
print(list2[:])	    # all of it
print(list[12:19:2]) # from element 2 until 19, step size 2

print(list2[-1])	#last element
print(list2[-2:])       #last 2 elements
print(list2[:-2])	#everything except the last 2

''' lists can be used to implement stacks and queues '''
stack = [12, 42, -87, 0, 3.5]
stack.append(91)	#push by appending to list
print(stack)
print(stack.pop())	#the pop function is available for all lists
print(stack)

''' implementing a queue using traditional list functions is inefficient. 
    So, we use a deque instead. '''
queue = deque([12,19, 8, 15, 25])
queue.append(150)	# append to add to queue
print(queue)
print(queue.popleft())	# popleft to remove from queue
print(queue)

''' The list structure comes with several other functions like sort and reverse'''
list3 = [5,2,-10,19,34, 6, 99,0]
list3.sort()
list3.reverse()
print(list3)