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Introduction to Python - Course Notes by Chinmay Garg

Introduction to Python

1. Python Basics

  1. Conceived by Guido Van Rossum (https://en.wikipedia.org/wiki/Guido_van_Rossum).
  2. Python is open source (free to use)
  3. Very easy to build packages (, which is code that you can share with other people to solve specific problems) in Python.
  4. "Swiss army knife" of programming languages

  1. To install packages hassle-free install pip install manager
  1. Python Shell - place where you can type code & immediately see results

  2. IPython Shell - Interactive Python, juiced up version of regular Python created by Fernando PĂ©rez (https://en.wikipedia.org/wiki/Fernando_P%C3%A9rez_(software_developer)) and is part of the broader Jupyter (https://jupyter.org/)

  1. Python Script - text files with the extension .py. It's a list of Python commands that are executed, almost as if you where typing the commands in the shell yourself, line by line.
  2. Putting your code in Python scripts instead of manually retyping every step interactively will help you to keep structure and avoid retyping everything over and over again.To make a change,simply make the change in the script, and rerun the entire thing.
  3. Add comments (#) to Python scripts - important to make sure that you and others can understand what your code is about.
# Addition
print(5+6)

Variable & Types

  1. Variable - "Save" values while coding to later call up by typing the name. Make your code reproducible.
  2. Variables have a specific type (int, float, str). Use type().
  3. A "sting" (str) is Python's and most programming languages way to represent text. Both '' and "" can be uset to represent strings.
  4. Booleans - very useful Ex. perform filtering operations (True, False)
a = 4 # (int)
b = 3 # (int)
c = a/b #(float)

type(c)
d = 'ab'
e = 'cd'
f = d + e

print(f)
type(f)
g = True
h = False
i = g + h # (results in integer value)
j = g or h # (use "or" for boolean algebra output)
print(i)
print(type(i))
print(j)
print(type(j)) # (use print to print "ALL" outputs. Otherwise only the latest one executes.)
# Example of using variables to store file paths as strings

# Define file paths
input_file_path = '/path/to/input/file.txt'
output_file_path = '/path/to/output/file.txt'

# Check the types of the variables
type(input_file_path), type(output_file_path)
# Example without raw string
file_path_escaped = "C:\Users\Name\Documents\file.txt"
print(file_path_escaped)

# Example with raw string
file_path_raw = r"C:\Users\Name\Documents\file.txt"
print(file_path_raw)
# Example without raw string
file_path_escaped = "C:\\Users\\Name\\Documents\\file.txt"
print(file_path_escaped)

# Example with raw string
file_path_raw = r"C:\\Users\\Name\\Documents\\file.txt"
print(file_path_raw)