Day 1 – Lesson 2 Fundamentals of Programming Languages Python Mini-Course University of Oklahoma Department of Psychology Python Mini-Course: Day 1 - Lesson 2 4/5/09
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Transcript Day 1 – Lesson 2 Fundamentals of Programming Languages Python Mini-Course University of Oklahoma Department of Psychology Python Mini-Course: Day 1 - Lesson 2 4/5/09
Day 1 – Lesson 2
Fundamentals of Programming
Languages
Python Mini-Course
University of Oklahoma
Department of Psychology
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Python Mini-Course: Day 1 - Lesson 2
4/5/09
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
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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
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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
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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
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Starting IDLE
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Programs
Programs are sequences of
instructions
Input
Output
Math and data manipulation
Conditional execution
Repetition
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The “Hello, World” program
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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
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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
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Debugging
You will make mistakes while
programming!
These mistakes are called
“bugs” and the process of
tracking them down and
eliminating them is debugging
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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
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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)
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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
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