This document outlines lessons from a Python mini-course on the fundamentals of programming languages. The objectives are to describe the basic structure of Python, use the IDLE interactive interpreter, and identify three types of errors. The lessons cover formal languages, how programming languages are used to express computations, translating between high and low-level languages using interpreters or compilers, the structure of programs, and debugging syntax errors, runtime errors, and semantic/logical errors.

1. Python Mini-Course
University of Oklahoma
Department of Psychology
Day 1 – Lesson 2
Fundamentals of Programming
Languages
4/5/09Python Mini-Course: Day 1 - Lesson 21

2. Lesson objectives
1. Describe the basic structure of the
Python language
2. Use the IDLE interactive
interpreter
3. Identify three kinds of errors that
occur in programming and
describe how to correct them
4/5/09Python Mini-Course: Day 1 - Lesson 22

3. Formal languages
Designed for specific apps
Ex: mathematical notation
Have strict rules for syntax
 3 + 3 = 6
 3+ = 3$6 (bad syntax)
Are literal and unambiguous
Structure is critical
4/5/09Python Mini-Course: Day 1 - Lesson 23

4. Programming languages
Formal languages that are
designed to express computations
and algorithms
Low level
One step removed from the 1’s and
0’s used by the computer
High level
More human-friendly languages
4/5/09Python Mini-Course: Day 1 - Lesson 24

5. Translating
High level language must be
translated into low level language
by either:
Interpreter (at run-time)
Compiler (creates a file containing
executable object code)
Python is an interpreted language
4/5/09Python Mini-Course: Day 1 - Lesson 25

6. Starting IDLE
4/5/09Python Mini-Course: Day 1 - Lesson 26

7. Programs
Programs are sequences of
instructions
Input
Output
Math and data manipulation
Conditional execution
Repetition
4/5/09Python Mini-Course: Day 1 - Lesson 27

8. The “Hello, World” program
4/5/09Python Mini-Course: Day 1 - Lesson 28

9. Scripts
A script is a file that contains a
program in a high-level
language for an interpreter
Python scripts are text files
ending in .py
Create HelloWorld.py
4/5/09Python Mini-Course: Day 1 - Lesson 29

10. Executing scripts
Python scripts are run in a
“shell”
This can be IDLE, a terminal shell
(OS X, Linux, Unix), or a
command prompt window (MS
Windows)
Run HelloWorld.py in IDLE
4/5/09Python Mini-Course: Day 1 - Lesson 210

11. Debugging
You will make mistakes while
programming!
These mistakes are called
“bugs” and the process of
tracking them down and
eliminating them is debugging
4/5/09Python Mini-Course: Day 1 - Lesson 211

12. Syntax Errors
All programming languages are
picky about syntax
Try this:
1 + 2) + 3
Syntax errors can be identified
using automated code checking
(color coding) and by error
messages
4/5/09Python Mini-Course: Day 1 - Lesson 212

13. Runtime errors
Errors that occur when
program is running
Also called “exceptions”
Ex: runtime.py
Identified by testing the
program (this includes using
test modules)
4/5/09Python Mini-Course: Day 1 - Lesson 213

14. Semantic or logical error
Program runs (and does
exactly what you told it to do)
But you made a mistake in the
design or implementation
Identified by case-based
testing
4/5/09Python Mini-Course: Day 1 - Lesson 214