列表：非常的灵活，可以存储任意的数据类型，还支持append（）方法，问题是浪费大量的空间
数组： 假设你知道 array 中所有的数据类型都是一样的话，那么你就可以在空间上节省一大半。
list 各种用法：
list.append('d') #will add 'd' to the listlist[0] #will get the first item 'a'list.insert(i, x) # Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x). list.pop(2) # will remove items by postion, remove the 2nd itemlist.remove(x) # Remove the first item from the list whose value is x.list.index(x) # Return the index in the list of the first item whose value is x. It is an error if there is no such item.list.count(x) # Return the number of times x appears in the list.list.sort(cmp=None, key=None, reverse=False) # Sort the items of the list in place (the arguments can be used for sort customization, see sorted() for their explanation).list.reverse() # Reverse the elements of the list, in place.