Package in Python

:dart: Learning Objectives

By the end of this lesson, you will:

• Understand what Python packages are and why we use them
• Learn how to import packages in different ways
• Use functions from the random and time packages
• Practice importing and using package functions

:information_source: What is a Package? A package is a folder that contains modules (files) and other folders with Python code for specific tasks. Think of it like a toolbox where each tool (function) is organized in compartments (modules)!

:package: Why Use Packages?

You've learned that functions help us perform specific tasks. But imagine writing every single function from scratch - that would take forever!

That's why programmers use packages - collections of pre-written code that we can use in our programs. Python has many ready-to-use packages!

Package Structure

Here's how packages are organized:

• Function: The smallest unit - a piece of code that does one task
• Module: A file containing many related functions
• Package: A folder containing many related modules

:memo: Remember the Flow! Function -> Module -> Package

Small pieces of code combine to form files, and files combine to form folders!

:wrench: How to Import Packages

Before using any function from a package, you must import it first. There are three main ways to import:

1. Import the whole package - using import
2. Import with a nickname - using import ... as
3. Import specific functions - using from ... import

Let's learn each method using the randint() function from the random package!

Method 1: Import the Whole Package

Use the import keyword followed by the package name. Then call functions using package.function():

import random
random.randint(1,10)

Expected output:

4

Method 2: Import with a Nickname

Sometimes package names are long. You can give them a shorter nickname using as:

import random as rd
rd.randint(1,10)

Expected output:

1

Method 3: Import Specific Functions

If you only need one function, import just that function. Then you can use it directly without the package name:

from random import randint
randint(1,10)

Expected output:

9

:bulb: Which Import Method Should I Use?

• Use import package when you need many functions from the package
• Use import package as nickname for packages with long names
• Use from package import function when you only need one or two functions

:emoji: The Random Package

Python has many built-in packages. Let's explore two very useful ones: random and time.

Useful Functions in the Random Package

The random package helps us work with random numbers and choices:

random() - Generate Random Decimals

Returns a random decimal number between 0 and 1:

random.random()

Expected output:

0.8722454090457804

randint() - Generate Random Integers

Returns a random whole number within your specified range:

random.randint(1,20)

Expected output:

19

shuffle() - Mix Up a List

Takes a list and randomly rearranges its items:

numbers = list(range(10))
random.shuffle(numbers)
print(numbers)

Expected output:

[4, 0, 2, 9, 8, 5, 7, 1, 3, 6]

:memo: Learn More! To discover more functions in the random package, visit: https://www.w3schools.com/python/module_random.asp

:alarm_clock: The Time Package

Useful Functions in the Time Package

The time package helps us work with time and dates:

localtime() - Get Current Time

Returns the current time with detailed information:

time.localtime()

Expected output:

time.struct_time(tm_year=2020, tm_mon=11, tm_mday=18, tm_hour=7, tm_min=7, tm_sec=11, tm_wday=2, tm_yday=323, tm_isdst=0)

sleep() - Pause Your Program

Makes your program wait for a specified number of seconds:

for i in range(5):      for i in range(5):
    print(i+1)              print(i+1)
    time.sleep(1)           time.sleep(1)

Expected output:

1                       1
2                       2
3                       3
4                       4
5                       5

:memo: Learn More! To discover more functions in the time package, visit: https://www.programiz.com/python-programming/time

:memo: Summary

In this lesson, you learned:

• Packages are organized collections of Python code
• You must import packages before using them
• Three ways to import: import, import...as, and from...import
• The random package helps with random numbers
• The time package helps with time-related tasks

Video

:emoji: AI Practice Prompts

Code with AI: Try using AI to work with Python packages!

Prompts to Try:

• "Help me import and use the math package to calculate the square root of a number."
• "Show me how to use the random package to generate a list of random numbers."
• "Write code using the datetime package to display the current date and time."

:dart: Practice Exercises

Try these challenges to test your understanding:

1. Random Game: Import the random package and create a number guessing game
2. Timer Challenge: Use the time package to create a simple countdown timer
3. Package Explorer: Choose a new package (like math or datetime) and explore three of its functions