![References
[1]http://effbot.org/zone/call-by-object.htm
[2]http://www.jeffknupp.com/blog/2012/11/13/is-python-callbyvalue-or-
callbyreference-neither/
[3]http://www.rafekettler.com/magicmethods.html
[4]http://www.silverwareconsulting.com/index.cfm/2012/7/24/Getting-Started-
with-virtualenv-and-virtualenvwrapper-in-Python
[5]http://excess.org/article/2013/02/itergen1/](https://image.slidesharecdn.com/css-130312005928-phpapp01/85/C-s-s-16-320.jpg)
C,s&s
- 1. Slightly Advanced Python Chai,Software and Samosa
- 2. Python's calling mechanism ● Everything is an object ● Variables are essentially names assigned to objects ● Variables are not containers in memory ● Call by value or call by reference?
- 3. Python's calling mechanism contd.. ● Call by sharing/Call by object/Call by object reference. ● Derived from a programming language called CLU. "We call the argument passing technique _call by sharing_, because the argument objects are shared between the caller and the called routine. This technique does not correspond to most traditional argument passing techniques (it is similar to argument passing in LISP). In particular it is not call by value because mutations of arguments per-formed by the called routine will be visible to the caller. And it is not call by reference because access is not given to the variables of the caller, but merely to certain objects."
- 4. Decorators ● In python , Functions are first class citizens ● They can be passed as an argument to a function and returned from a function. ● Decorators are syntactic sugar. ● functools.wraps
- 5. Iterables and Iterators Wrong ways of looping in python 1. Using while 2. Using range(len()) with indices The pythonic way for x in iterable: How does this work?
- 6. Iterators and Iterables How to define a custom iterator for the class? Difference between iterables and iterators? Why use an iterator? Why not use an iterator?
- 7. Generators Most commonly used as a easy way of defining iterators Yields control to the callee but keeps record of the local variables and point of execution Resumes from where it left off on the next call. Generators as coroutines
- 8. Useful functions for working with iterators and iterables ● enumerate for seeing both indices and value ● iterkeys for seeing both keys and values ● itertools ○ chain for combining various iterators ○ tee for creating mutliple iterators from a single iterable ○ izip , just like zip but returns an iterator
- 9. Magic Methods A way to mimic python's built in objects Classes of Magic Methods: 1. Object creation and Destruction 2. Magic Methods for Comparisons 3. Arithmetic operators: ● Unary Operators ● Normal Arithmetic Operators ● Reflected Arithmetic Operators ● Augmented Assignment
- 10. Magic Methods(contd..) 4. Type conversion magic methods 5. Representing your classes(__str__,__repr__, __hash__,__nonzero__, etc.)
- 11. Magic Methods (contd.- Controlling Attribute Access) ● __getattr__, __setattr__, __delattr__, __getatrribute__ ● Useful to define access control on attributes ● Care to be taken to avoid infinite recursion
- 12. Magic Methods (Writing your own container) ● __len__, __getitem__, __setitem__, __delitem__, __iter__ , __reversed__ , __contains__, __missing__ ● Writing your own container class
- 13. Magic Methods (Wrapping up) ● Make your class instances behave like functions by defining the magic method __call__ ● Context Managers for use with the with keyword.(__enter__ , __exit__ methods) ● Other magic methods for defining copying operations,pickling , descriptors etc.
- 14. VirtualEnv ● Tool to create isolated python environments. ● Great to test new versions of libraries and re-creating production environments ● Using virtualenv ○ Install virtualenv and virtualenvwrapper through pip ○ Add these two lines to your bashrc export WORKON_HOME=$HOME/.virtualenvs source /usr/local/bin/virtualenvwrapper.sh
- 15. Virtual Env commands 1. mkvirtualenv 2. rmvirtualenv 3. workon 4. deactivate