Reference code snippets for the Python programming language.

1 Check Python installed Version

 > python --version
Python 3.9.7

2 Hello World Program

Filename: firstpythoncode.py

print("Hello, World!")

Run the programin from terminal

>python firstpythoncode.py

3 Comments

Single line comments

#Print Hello Python on Console
print("Hello Python")

Multiline comments

#Below code displays
#Hello World
print("Hello, World!")

"""
Below code displays
Hello World
"""
print("Hello, World!")

Python will ignore string literals if no assingnment used.

msg = """
Below code displays
Hello World
"""
print(msg)

Output

Below code displays
Hello World

4 Variables

a = 100
name = "abhi"

type() funciton

print(type(a)) #<class 'int'>
print(type(name)) #<class 'str'>

Ilegal variable names

2varname = "Abhi"
var-name = "Abhi"
var name = "Abhi"
#SyntaxError: invalid syntax

Legal Variable Names

var_name = "Abhi"
varName = "Abhi"
_var_name = "Abhi"
VARNAME = "Abhi"
varname1 = "Abhi"

5 Keywords

Keywords words can't be used as variable and function names.

Program to print all keywords

# importing the module
import keyword
print(keyword.kwlist)

Output

['False', 'None', 'True', 'and', 'as', 'assert', 'async', 'await', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

and = "Hello"
#SyntaxError: invalid syntax

6 Identifiers

Todo

7 Constants