Python - A Systematic Introduction¶
Well, maybe not too systematic
Python is an easy to learn, powerful programming language. It has efficient high-level data structures and a simple but effective approach to object-oriented programming. Python’s elegant syntax and dynamic typing, together with its interpreted nature, make it an ideal language for scripting and rapid application development in many areas on most platforms.
(Quote from the Python documentation)
Python is also used for large scale applications. There are thousands of powerful extension modules for all areas of applications. Both Python’s standard library and the community-contributed modules allow for endless possibilities.
- Web and Internet Development
- Database Access
- Desktop GUIs
- Scientific & Numeric
- Education
- Network Programming
- Software & Game Development
Python Programs¶
A Python program is sequence of statements saved as a text file. Each text file is called a module. Most applications consist af many modules.
Python is an interpreted language. There is no explicit compile step required, which allows for a fast developement cycle. When a Python program is started, the program text is translated into a bytecode, and the resulting bytecode is actually executed. The bytecode translation also performs some syntax checks.
A first example¶
# our first python program
cakes = 3
persons = 8
cakespp = cakes / persons
print("cakes per person:", cakespp)
cakes per person: 0.375
The above program consists of a comment, 3 assignments and a function call (print is a built-in function). The execution of the programs gives one line of output. There is no declaration of variables, no semicolon, no braces.
An assignment links a name with an object. Left of the equal sign is a name, the expression on the right is an object or is used to create an object.
The print() function creates text, which is directed to an output channel, often this is the console.