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Standard Library & Third-Party Libraries

Question: Can you list some modules provided by the Python standard library?

“math”, …

Section 1. Libraries, Package, Module ?

What’t the different among them three ?

Library: Focusing on the function. May include multiple pacakges and modules.

Package: A folder with multiple Modules

Module: A .py file

Pre-installed tools with Python
Examples: math

Try this in Python:

import math
print("Pi is approximately", math.pi)
print("Square root of 16:", math.sqrt(16))

Python’s Built-in Help

Discover all available standard libraries:
```
help('modules')
```

Third-Party Libraries

Extra tools you can download
Massive collection at PyPI.org
Example popular libraries:
- pandas (data wizardry)
- requests (web communication)
- numpy (number crunching)

Three Ways to Use Libraries

Full Import - Get the whole toolbox:

import math
print("2^5 =", math.pow(2, 5))

Import Method 2: Precision Pick

Specific Import - Grab just what you need:

from random import randint
print("Random dice roll:", randint(1, 6))

Import Method 3: Nicknames

Alias Import - Make it short:

import pandas as pd
data = {'Birds': ['Eagle', 'Penguin'], 'Speed': [320, 8]}
df = pd.DataFrame(data)
print(df)

Why Different Import Methods?

Full imports prevent name conflicts
Specific imports make code cleaner
Short Name save typing long names

Let’s Mix Them Up!

Combine different import styles:

from math import sqrt as sq
print("Square root of 121:", sq(121))

Your Coding Toolkit Now Has…

Standard Library: Always available
Third-Party Libraries: Expand your powers
Import Skills: Use any library effectively

Demo

# Random password generator
from random import choice
chars = 'ABC123!@'
password = ''.join([choice(chars) for _ in range(8)])
print("Your new password:", password)

Pro Tip: Explore Libraries!

Standard library documentation: docs.python.org/3/library
PyPI for new discoveries: pypi.org
Remember: Great programmers stand on the shoulders of giants 🏗

Section 2. Standard Library

math, time, random，os

Other modules:

datetime Module - Current Time

import datetime

now = datetime.datetime.now()
print("Current time:", now)

Output shows:

Year/Month/Day
Hour:Minute:Second.Microsecond

datetime Calculation with timedelta

future_date = now + datetime.timedelta(days=3)
print("Date after 3 days:", future_date.date())

timedelta supports:
- days
- hours
- minutes

######

Quesion: How to add “datetime” functions into the “ai.py”?

Section 3. Use pip to install third-party libraries.

pip - Python’s Package Manager

$ pip3 --version
pip 24.0 from ... (python 3.7)

Built-in tool for package management
Comes with Python 3.4+
Main commands: install/uninstall/list

Installing Your First Package

$ pip3 install requests
Collecting requests...
Successfully installed requests-2.31.0

Installs from Python Package Index (PyPI)
Installs to system/site-packages directory
Verify with pip list

Exploring Installed Packages

$ pip3 list
Package    Version
---------- -------
pip        21.2.4
requests   2.31.0
setuptools 57.4.0

Shows all installed packages
Includes version information
Helps manage dependencies

Speeding Up Downloads (use mirror)

$ pip3 install -i https://pypi.tuna.tsinghua.edu.cn/simple pandas

Why mirrors matter
Popular mirrors: Tsinghua, AliCloud
Temporary vs permanent configuration

Permanent Mirror Configuration

$ pip3 config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple

Create pip.conf file
Location: ~/.config/pip/pip.conf
Applies to all future installations

Let’s Use requests!

import requests

response = requests.get("https://www.baidu.com")
print(f"Status Code: {response.status_code}")
print(f"Response Text: {response.text[:100]}...")

Popular HTTP library
Simple API for web requests
Handles JSON responses

Real-World Example: Weather Check

import requests

city = "Beijing"
url = f"http://wttr.in/{city}?format=3"
response = requests.get(url)
print(f"Weather in {city}: {response.text}")

Sample output:

Weather in Beijing:  +25°C

Question: How can we add this function into ai.py?

QuestionL How can we learn more about “requests”?

Upgrading Packages

$ pip3 install --upgrade requests
$ pip3 install requests==2.31.0

Get latest features
Security updates
Watch for breaking changes

Section 4. A Formal Weather Reporter

Goal: Combine web data and time handling

What We’ll Use:

requests - Fetch data from websites
datetime - Handle dates/times

Try this first:

import datetime
current_time = datetime.datetime.now()
print(f"Hello! It's {current_time:%H:%M} now!")

Get Weather Data

Here’s a simple weather API example:

import requests

def get_weather(city):
    url = f"http://wttr.in/{city}?format=%t+%C"
    response = requests.get(url)
    return response.text

print(get_weather("London"))

Combine Time & Weather

Let’s make it friendly! ✨

def weather_report(city):
    time_now = datetime.datetime.now().strftime("%H:%M")
    weather = get_weather(city)
    return f"[{time_now}] Weather in {city}: {weather}"

print(weather_report("NewYork"))

Question: Is there something wrong? How can we fix it? Hint: we are using the Beijing Time.

Section 5. File Backup Helper

Goal: Automate file copying

File Tools:

os - Handle paths
shutil - File operations

Path check example:

import os

my_folder = "documents"
if not os.path.exists(my_folder):
    os.makedirs(my_folder)
    print(f"Created {my_folder}!")

Simple Backup Script

Copy all text files:

import shutil

def backup_files(src_folder, dst_folder):
    for file in os.listdir(src_folder):
        if file.endswith(".txt"):
            shutil.copy2(os.path.join(src_folder, file), dst_folder)
            print(f"Copied {file}!")

backup_files("notes", "backup")