Python Programming

Python Programming

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  PHYTHON PROGRAMMING SAMEER PATIL
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  Points To Remember Python was develop by Guido Van Rossum in 1991.  Python is high level language that contain feature of functional programming language like C and Object Oriented Programming Language like Java.  A group of objects having same behavior comes under same class.  Standard python compiler Is written in C language and hence called Cpython.  There are other flavors of python namely Jpython, IronPython and Pypy.  A python program contain source code that is first compiled by Python compiler to produce byte code. This byte code is given to Python Virtual Machine which converts the byte code to machine code so that processor will execute it and display result.  Python byte code is set of instruction created by Python development team to represent all type of operation. Each Byte code occupies 1 byte of memory and hence name Byte code.  PVM is the software containing an interpreter that converts the byte code into machine code depending on the OS and hardware of computer system where the python program runs.
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   The standardPVM is most often called Python Interpreter  PVM contains only an interpreter and hence Python is called an Interpreter Language  The programmer need not allocate or deallocate memory in Python. It is the duty of PVM to allocate or deallocate memory for python program.  Memory manager is a module in PVM which will allocate memory for objects. Garbage collector is another module in PVM that will deallocate memory for unused objects.  The programmer need not call the Garbage collector. It will execute automatically when the python program is running in memory.  In addition ,the programmer can also call the garbage collector whenever needed.  The files that contain Python Program along with Python compiler and libraries that can be executed directly are called as Frozen binaries.  The PY_COMPILE module converts a python source file into a .pyc file that contain byte code instruction. Generally .pyc files are provided to the end user.
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  Data Types inPython  Comments in Python Single line comments Multiline Comments DocString- if we are write string inside multiline comments and if these are written as first statements in a module ,function ,class or methods, then these string are call DocString. Api documentation Example Python –m pydoc –w demo for api documents
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  How Python seesVariable Data types in Python None Type Numeric Type Sequence type Sets Mapping
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  None type  Thenone datatype represent an object that doesn't contain any value. In java it refer as Null whereas in Python it called as None.  In python program maximum of only one none value is provided.  It is used inside the function as default value of arguments.  None datatypes is known as false.
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  Numeric Type There arethree sub type Int , float, complex Int no max upper limit . Float value also can written in exponential format Complex Data types- number format is like this a+bj or a+bJ. Here a is real and b is imaginary
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  Binary octal andHexadecimal code