Python Built-in & External Modules Guide

📦 Built-in (Standard Library) Modules

os

Interact with operating system

import os
print(os.getcwd())
print(os.listdir())

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sys

Python runtime information

import sys
print(sys.version)
print(sys.argv)

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math

Mathematical operations

import math
print(math.sqrt(25))
print(math.pi)

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random

Generate random values

import random
print(random.randint(1, 10))

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datetime

Date and time handling

from datetime import datetime
print(datetime.now())

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itertools

Efficient looping tools

import itertools
print(list(itertools.permutations([1,2,3], 2)))

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json

JSON data handling

import json
data = {"a": 1}
print(json.dumps(data))

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re

Regular expressions

import re
print(re.search(r"\d+", "Age 22").group())

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time

Time-related functions

import time
print(time.time())

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shutil

High-level file operations

import shutil
                        print(shutil.disk_usage("."))

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statistics

Mathematical statistics

import statistics
print(statistics.mean([10, 20, 30]))

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csv

Read and write CSV files

import csv
print(list(csv.reader(["a,b,c"])))

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threading

Multithreading support

import threading
print(threading.current_thread().name)

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functools

Higher-order functions & decorators

from functools import lru_cache

@lru_cache()
def square(n): return n*n

print(square(4))

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zipfile

Work with ZIP archives

import zipfile
print(zipfile.is_zipfile("test.zip"))

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logging

Application logging system

import logging
logging.warning("This is a warning")

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hashlib

Secure hash algorithms

import hashlib
print(hashlib.md5(b"hello").hexdigest())

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pathlib

Object-oriented filesystem paths

from pathlib import Path
print(Path.cwd())

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collections

Advanced data structures

from collections import Counter
print(Counter([1,2,2,3]))

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🌐 External (Third-Party) Modules

requests

HTTP & API requests

import requests
r = requests.get("https://api.github.com")
print(r.status_code)

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numpy

Numerical computing

import numpy as np
arr = np.array([1,2,3])
print(arr * 2)

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pandas

Data analysis

import pandas as pd
df = pd.DataFrame({"A":[1,2]})
print(df)

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flask

Web development

from flask import Flask
app = Flask(__name__)

@app.route("/")
def home():
    return "Hello"

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