Download Python Programming Language

Python Programming Language
by Vasu Chetty
Origins of Python
• Created by: Guido van Rossum, a Dutch
Programmer
• Created during: Christmas Break, 1989
• Created because: Guido had some free time
and an idea for an interpreter
• Named after:
Python Through the Ages
• Version 0: Inheritance, exception handling,
functions, and core data types of list, str and
dict
• Version 1: Lambda, reduce(), filter(), and
map()
• Version 2: Garbage collection and generators
• Version 3: Unification of str/unicode types,
statements switched to function calls, and
instances of list replaced by views and
iterators
Why Python?
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Freely available
Well-documented
Fosters rapid development
Very high-level object-oriented language
Integration facilities for mixed-language
development
Who uses Python?
• Google (e.g. code.google.com was written in
Python)
• New York Stock Exchange (web-based transaction
system)
• YouTube
• NASA
• Other common uses include: RSS readers, CGI
applications, generating and analyzing logs, and
creating HTML calendars
Python Programming Paradigms
(say that 10 times fast)
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Object-oriented
Iterative (generators)
Imperative (follows sequential steps)
Functional (lambda calculus)
Common Data Types and Elements
• Numbers: integer, floating point, complex
• Other: boolean, none, string, tuple, list,
dictionary, set
• Conditionals: if, else, elif
• Loops: while, for
• Supports: nested loops, function
calls from other functions, string
concatenation, combined boolean,
string, or integer in conditional with
“and” or “or”
Functions in Python
• Functions are essentially objects, making
them very flexible
• Functions are considered as first class, so they
can be passed to and from other functions
• Return values need not be set, return none
statements are implicitly built in
• Functions can be nested within other
functions
Pass-by-value or Pass-by-reference
• All parameters in Python are pass-by-reference,
but some appear to act as pass-by-value because
of the difference between mutable and
immutable objects
• String, tuples and numbers are immutable,
altering them will create a new instance
• Lists and dictionaries are mutable, altering them
will also change the original object
Type Checking: Dynamic and Strong
• Python has dynamic type checking, which means
all types are resolved at run-time rather than at
compile time
• Python uses strong type checking, ensuring type
errors are thrown for mismatches in type
• As of version 3, Python no longer supports type
coercion
• Static type inference is not possible in Python
Object-orientedness
• Python supports multiple inheritance
• Python utilizes static variable and static
method inheritance
• Super(), in version 3 of
Python, is invoked
dynamically and calls the
superclass method of the
same name
Conclusion
• Python is an easy-to-use, robust programming
language that is freely available
• Python’s objects and functions are very
versatile
• Python is a very high-level object-oriented
language
• Python is awesome!