Introduction to Python
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The document provides an overview of Python, highlighting its features such as simplicity, readability, and dynamic typing, while comparing it to C and Java. It explains memory management in Python, which is automatic with garbage collection, and contrasts Python's object-oriented approach with C's procedural orientation. Additionally, it discusses execution processes and key differences in data type handling, exception management, and memory allocation between Python and C.
Introduction to Python
- 2. Python ● Combines the features of C and JAVA ● It offers elegant style of developing programs like C ● It offers classes and objects like Java
- 3. Features of Python ● Simple ● More clarity ● Less stress on reading and understanding the syntax ● Easy to learn ● Uses very few keywords ● Very simple structure, resembles C ● Open source ● High level language ● Dynamically typed ● Type of the variable is not declared statically
- 4. Features of Python... ● Platform Independent ○ Python compiler generates byte code ○ PVM interprets the byte code ● Portable ● Procedure and Object oriented language ● Interpreted ● Extensible ● Embeddable ● Huge Library ● Scripting Language ● Database Connectivity ○ Provides interfaces to DB like Oracle, Sybase or MySql
- 5. Execution of a Python Program ● Example: ● x.py → python_compiler → x.pyc → PVM → Machine_Code ● python -m py_compile x.py ● python x.cpython-34.py ● python -m dis add.py
- 6. Memory Management in Python ● In C or C++, allocation and deallocation of memory will be done manually ● malloc(), calloc(), realloc() or free() ● In python, it is done at run time automatically ● Memory Manager inside the PVM takes care of allocating memory for all objects in Python. ● All objects are stored in Heap
- 7. Garbage Collection in Python ● Garbage collector is a module in Python that is useful to delete objects from memory which are not used in the program. ● The module that represents the GC is gc. ● It will keep track of how many times the object is referenced. ● If it is referenced 0 times, then gc will remove object from memory.
- 8. C Vs Python C Python Procedure Oriented language Object Oriented language Faster Slower Compulsory to declare the data types of variables Data Types are not required Type discipline is static and weak Dynamic and strong Pointers concept present No pointers concept No exception handling facility Exception handling facility is robust Do-while is present Absent Has switch statement No Switch
- 9. C Vs Python C Python Manually allocate the memory Automatic Absence of GC GC is present Supports Single and multi dimensional arrays Supports only single dimension Array should be positive Can be Positive or negative Array bounds checking is not present Present Indentation is not necessary Strictly needed Every statement is terminated by ; No semicolon