Python for A-Level CS

2:07 Lesson 1 Nested loops One loop inside another sounds simple, and one sentence about it gets misread every year: for every sing… 2:02 Lesson 2 Text files Opening a file takes a mode, and the mode is not a formality. Read gives you what is there. Write throws… 2:06 Lesson 3 Exceptions Ask Python to turn the word hello into a number and it raises an exception — a value error. And an excep… 2:10 Lesson 4 Stacks A stack is the first abstract data type in this course, and the word abstract is doing real work. What d… 2:09 Lesson 5 Queues A stack hands back what you put in last. That is exactly the wrong thing for anything waiting its turn. … 2:11 Lesson 6 Linked lists An array has to know its size before it holds anything, and growing one means copying the lot. A linked … 2:21 Lesson 7 Searching Finding a value in a list is the first algorithm anyone writes. It is still taught because the obvious w… 2:02 Lesson 8 Sorting Bubble sort only ever looks at neighbours. Walk the list and compare each pair in turn, swapping any tha… 2:18 Lesson 9 Recursion Some problems shrink into smaller copies of themselves, and a loop is a clumsy way to say so. Recursion … 2:44 Lesson 10 Classes & objects So far you have used types somebody else invented. The moment your problem has a Student in it, none of … 2:23 Lesson 11 Inheritance & encapsulation Copy a class to change one method and you have made a second copy of every bug in it. Inheritance lets a… 2:53 Lesson 12 Programming paradigms The same problem, written twice, can look like two different subjects. That difference has a name, and t… 2:40 Lesson 13 Hash tables A hash table is a list of slots, and the trick is that you never look for anything. You compute where it… 2:47 Lesson 14 Binary search trees A sorted list is fast to search and slow to change. A tree refuses to choose between the two. A binary s… 2:22 Lesson 15 Graphs A road map, a friend list and a network of routers are the same object. Once you see that, one set of al…