Python - Points to Remember

Introduction

Python is an open-source object-oriented programming language
Python uses an interpreter instead of a compiler - An interpreter is a computer program that directly executes, i.e. performs, instructions written in a programming or scripting language, without requiring them to have previously been compiled into a machine language program
Python can be used to build packages that can be shared and reused in other programs
Python is a versatile language. It can be used to do any quick calculations for web-site development.
Python shell is an editor where we can write any command and execute it instantly. For simple calculations, we can directly write 7+8 into the Python shell and see the result (i.e., 15).

A Python module is a script file with the extension “.py”
Python modules contain a sequence of definitions and statements. Python executes these statements in a specific, consistent, and predictable order list. Each of the Python statements contain zero or more expressions.
To add comments to your Python script, you can use the # tag

A Python expression describes a computation, or operation, performed on data. For example, the arithmetic expression 2+1 describes the operation of adding 1 to 2. An expression may contain sub-expressions, for example, the expression 2+1 contains the sub-expressions 2 and 1.
Python evaluates an expression by first evaluating its sub-expressions, then performing an operation on the values. For example, to evaluate 2*10 + 6/3, Python first evaluates 2*10 to the value 20, then evaluates 6/3 to the value 2, then adds the two to get 22.
Python support four types of expressions (i.e., Literal, Binary, Compound, and Unary Expressions)
A literal expression evaluates to the value it represents. For example, 17, 'this is some text', 8.125 and True
A binary expression consists of a binary operator applied to two operand expressions. A binary operator is an operator that takes two arguments (for example, + or /). For example:

A compound expression contains multiple expressions and at least one of the operands is itself an expression. For example, 2 * 5 + 1 is equivalent to (2 * 5) + 1.
To evaluate a compound expression to a value, 1. Use the order of operations to identify the main operator (the last operator that you’ll apply). For example, the main operator in 2 * 5 + 1 is +, so 2 * 5 + 1 is an addition expression. So, 2 * 5 and 1 are two operands of + and it gives a result equal to 11. In compound expression, use parentheses to override Python’s order of operations.

Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in memory. Python variables do not need explicit declaration to reserve memory space. The declaration happens automatically when you assign a value to a variable, for example:
1. s="Hello World";

Variables declared are case-sensitive, for example:
1. s="Hello Friends";
2. S="Hello World";
This will initialize two different variables named “s” and “S” and assign the values ‘Hello Friends’ and ‘Hello World’ to the variable ‘s’ and ‘S’

Python is perfectly suited to do basic calculations. Apart from addition, subtraction, multiplication and division, there is also support for more advanced operations such as:
Exponentiation: **. This operator raises the number to its left to the power of the number to its right. For example, 4**2 will give 16.
Modulo: %. This operator returns the remainder of the division of the number to the left by the number on its right. For example, 18 % 7 equals 4.

In this blog, we learned about some important points of Python Programming language to remember.

Next Recommended Reading Setting Up Python Environment for Python 2.7