Lab2

Question 1
"""
-------------------------------------------------------
Array version of the Stack ADT.
-------------------------------------------------------
Author:  Kevin Lin
ID:      180419860
Email:   linx1986@mylaurier.ca
Section: CP164 Lec:B Lab:3
__updated__ = "2019-01-21"
-------------------------------------------------------
"""
from copy import deepcopy

class Stack:

    def __init__(self):
        """
        -------------------------------------------------------
        Initializes an is_empty stack. Data is stored in a Python list.
        Use: s = Stack()
        -------------------------------------------------------
        Returns:
            a new Stack object (Stack)
        -------------------------------------------------------
        """
        self._values = []

    def is_empty(self):
        """
        -------------------------------------------------------
        Determines if the stack is empty.
        Use: b = s.is_empty()
        -------------------------------------------------------
        Returns:
            True if the stack is empty, False otherwise
        -------------------------------------------------------
        """

        return self._values == []

    def push(self, value):
        """
        -------------------------------------------------------
        Pushes a copy of value onto the top of the stack.
        Use: s.push(value)
        -------------------------------------------------------
        Parameters:
            value - a data element (?)
        Returns:
            None
        -------------------------------------------------------
        """

        self._values.append(deepcopy(object))

    def pop(self):
        """
        -------------------------------------------------------
        Pops and returns the top of stack. The value is removed
        from the stack. Attempting to pop from an empty stack
        throws an exception.
        Use: value = s.pop()
        -------------------------------------------------------
        Returns:
            value - the value at the top of the stack (?)
        -------------------------------------------------------
        """
        assert len(self._values) > 0, "Cannot pop from an empty stack"

        value = deepcopy(self._values[-1])
        del self._values[-1]

        return value

    def peek(self):
        """
        -------------------------------------------------------
        Returns a copy of the value at the top of the stack.
        Attempting to peek at an empty stack throws an exception.
        Use: value = s.peek()
        -------------------------------------------------------
        Returns:
            value - a copy of the value at the top of the stack (?)
        -------------------------------------------------------
        """
        assert len(self._values) > 0, "Cannot peek at an empty stack"

        value = deepcopy(self._values[-1])

        return value


    def __iter__(self):
        """
        FOR TESTING ONLY
        -------------------------------------------------------
        Generates a Python iterator. Iterates through the stack
        from top to bottom.
        Use: for v in s:
        -------------------------------------------------------
        Returns:
            value - the next value in the stack (?)
        -------------------------------------------------------
        """
        for value in self._values[::-1]:
            yield value

Question 2
def array_to_stack(s, a):
    """
    -------------------------------------------------------
    Pushes contents of source onto stack. At finish, source is empty.
    Last value in source is at bottom of stack,
    first value in source is on top of stack.
    Use: array_to_stack(s, a)
    -------------------------------------------------------
    Parameters:
        s - a Stack object (Stack)
        a - a Python list (list)
    Returns:
        None
    -------------------------------------------------------
    """
    for _ in range(len(a)):
        value = a[-1]
        a.pop(-1)
        s.push(value)

Question 3
def stack_to_array(stack, target):
    """
    -------------------------------------------------------
    Pops contents of stack into target. At finish, stack is empty.
    Top value of stack is at end of target,
    bottom value of stack is at beginning of target.
    Use: stack_to_array(stack, target)
    -------------------------------------------------------
    Parameters:
        stack - a Stack object (Stack)
        target - a Python list (list)
    Returns:
        None
    -------------------------------------------------------
    """
    while not stack.is_empty():
        value = stack.pop()
        target.insert(0,value)

Question 4
def stack_test(source):
    """
    -------------------------------------------------------
    Tests the methods of Stack for empty and
    non-empty stacks using the data in source:
    is_empty, push, pop, peek
    (Testing pop and peek while empty throws exceptions)
    Use: stack_test(source)
    -------------------------------------------------------
    Parameters:
        source - list of data (list of ?)
    Returns:
        None
    -------------------------------------------------------
    """
    s = Stack()
    a = []
    array_to_stack(s, source)
    print("The stack is empty: {}".format(s.is_empty()))
    print("Top of the stack: {}".format(s.peek()))
    print("Pushes 5 into stack: {}".format(s.push(5)))
    print("Pops top element: {}".format(s.pop()))
    print("Top of the stack: {}".format(s.peek()))

    stack_to_array(s, a)

Question 5
"""
-----------------------------------------
question 5
-----------------------------------------
Author: Kevin Lin
ID: 180419860
Email: linx1986@mylaurier.ca
----------------------------------------
"""
from utilities import stack_test
from Movie_utilities import read_movies


source = []
fv = open("movies.txt", "r")

source = read_movies(fv)

stack_test(source)