Videos
Python for IGCSE CS
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14 video lessons
2:04
Lesson 1
Sequence, input, output
The syllabus starts with a word that sounds too simple to need naming: sequence. A program is a list of steps, and Python runs them from the top down, one at a…
2:14
Lesson 2
Variables and types
A variable is a named box that holds a value. You put a value in with an equals sign, and that act has a name in the syllabus: assignment. Worth noticing…
2:10
Lesson 3
Selection
Selection is the second big idea in the syllabus: choosing what to do, based on a test. The test gives back true or false, and the program goes one way if it…
2:18
Lesson 4
Iteration
Iteration means repeating steps, and the everyday loop is the one that repeats a fixed number of times. In Python that is for i in range. Range on its own…
2:07
Lesson 5
Totalling and counting
Adding up a list of numbers has a name in the syllabus: totalling. It works with one extra variable that remembers the answer so far. The total starts at…
2:14
Lesson 6
Procedures and functions
A function is a named block of code. You write it once with def, and then run it whenever you like by writing its name. Here it is called twice, so it prints…
2:23
Lesson 7
Validation
Whatever you ask for, someone will type something else. An age of forty-five is fine. An age of nine hundred is not, and neither is a negative age — but the…
2:13
Lesson 8
Arrays
Suppose you have three scores. You could use three variables — but then thirty scores needs thirty names, and you cannot write a loop over names. An array…
2:03
Lesson 9
Two-dimensional arrays
A table of marks, a seating plan, a game board — these have rows and columns, and one index is not enough. A two-dimensional array is a list of lists: each…
2:07
Lesson 10
Searching, max and min
A linear search looks at each item in turn until it finds what it wants, and stops as soon as it finds it. The syllabus names it, so expect the phrase on the…
2:02
Lesson 11
Bubble sort
Every sort is built on one move: exchanging two values. Python has a shortcut that does it in a single line. The exam does not, and wants three lines and a…
2:09
Lesson 12
Text files
Variables vanish when a program ends; a file does not. Working with one always takes three steps, and the exam expects all three. Open the file, naming it and…
2:09
Lesson 13
Databases and SQL
A database keeps data in tables, and a table looks like a spreadsheet: rows and columns. Each row holds everything about one thing — one student here — and it…
2:19
Lesson 14
Boolean logic
A Boolean value is either true or false, and there are exactly three operators that combine them. AND is true only when both sides are true. OR is true when at…