python examples

Practice with Jupyter Notebook, Python, and Algorithms

git commit -am "Release v0.3.0"
git tag -a v0.3.0 -m "Release v0.3.0"
git push origin master
git push origin v0.3.0

• Python defines a default constructor in the class, which exists regardless of created constructor unlike Java.
• Python has duck typing so it doesn't enforce type hints at runtime. It only cares about if the object has existing methods. Java is statically typed and enforces strict inheritance rules at compile time, so a parent object passed into an argument expecting a child class will raise a compile time error.
• Python has mutable default arguments, so use None on the list instead.
• In Python, modifying a list cannot be done while iterating over it.
• Python has double equal sign that checks for value equality. is confirms if two objects/variables are the same, so:

  a = 256
  b = 256
  print(a is b)

  • The print statement returns True because Python optimizes by caching small values -5 to 256 and short strings into memory. However, if the two variables were assigned to 257, they are not equal.
  • Defining a mutable value in python class body updates the value to be shared by all instances of the class.
• In exception handling, we have a try finally statement that both contain return 1 and return 2 then finally return would hijack the execution. Finally should not contain return statements.
• For multithreaded work, CPU bounded work will run slower due to competition for a single lock. For I/O heavy work, GIL is released when waiting on network responses and threading works good for I/O tasks.
• For circular imports, we can avoid this by defining a third file or by doing a local import within a method or local scope.
• += mutates in place but a = a + [1] creates a new list.
• __eq__ verifies object representation of the same value. When used in a set/dictionary, __hash__ needs to be implemented.
• @staticmethod in python is a normal function that lives in the class's namespace.