Set up

python3 -m venv venv
source venv/bin/activate

Upgrade

python -m pip install --upgrade pip

Python naming

Concept	Naming
Function and Variable Names	Lowercase with underscores (snake_case)	string_utils.py,math_helpers.py
Class Names	Camel	class DataLoader:
Global Variable (Private)	Prefix with an underscore _	_internal_var = 42

Jackpot

No, you do not need to add a semicolon (;) at the end of every statement in Python. Python uses line breaks to determine the end of a statement, making ; optional in most cases.

Concept	Code
HashMap	dict()

Remove Duplicate

    nums = list(set(nums))  # remove duplicates

MAX / MIN

Int

import sys

INT_MAX = sys.maxsize        # usually 2**63 - 1 on 64-bit systems
INT_MIN = -sys.maxsize - 1   # usually -2**63

Float

    max_value = float('-inf')  # for smallest possible value
    min_value = float('inf')   # for largest possible value

Swap

    # Swap elements at index 1 and 3
    arr[1], arr[3] = arr[3], arr[1]

• will take up extra space

Mid

    mid = left + (right - left) // 2

Sum

    expected_sum = n * (n + 1) // 2

Range

range(start, stop, step)

    for i in range(10, 0, -1):
        10
        9
        8
        7
        6
        5
        4
        3
        2
        1