Impression of Week 7

      LinkedList was introduced to us this week. And we are using that to do iteration and mutation.
      The way to solve LinkedList problems is iteration. We go over every element in the linked list and find what we want, then we make mutations.
      For example, the __contains__ method we did in the lecture:

def __contains__(self, value):
        ''' (LinkedList, object) -> bool

        Return whether LinkedList (self) contains value.

        >>> lnk = LinkedList()
        >>> lnk.prepend(0)
        >>> lnk.prepend(1)
        >>> lnk.prepend(2)
        >>> lnk.__contains__(1)
        True
        >>> lnk.__contains__(3)
        False
        '''
        cur_node = self.front
        while cur_node:
            if cur_node.value == value:
                return True
            cur_node = cur_node.nxt
        return False

      In this example, we are checking if value is in a linked list. Our thought was to go over all the nodes in the linked list, check every one of them to see if it has the same value as value. So, we store the node we are checking in a variable called cur_node, as we go deeper into the linked list, cur_node changes. If cur_node's value is equal to value, we return True, if not, we set cur_node to the next node and keep checking. When we go over all the nodes and nothing is returned, that means there are no value in the linked list, so we return False.