CodeBlanks Logo Icon CodeBlanks
Login Register

Standard library

Learn standard modules like math, random, datetime.

The standard library

The collection of modules that ships with Python is called the standard library. It requires no installation; you use it with import right away:

import math       # sqrt, pi, log
import random     # randint, choice
import datetime   # date, timedelta
import statistics # mean, median

These modules are maintained by the Python community and work on all platforms. Their functions are tested and documented.

They handle many tasks without installing third-party packages.

Common modules

Some modules in the standard library are used often in daily work. math for mathematical functions, random for randomness, datetime for dates and times, statistics for statistics:

import statistics
print(statistics.mean([1, 2, 3, 4]))
# 2.5

import datetime
print(datetime.date.today())
# 2025-01-15

These modules are reliable and fast in their domains. It is wise to check the standard library before turning to third-party packages.

Practice Mean with statistics.mean

Write import statistics. Then write print(statistics.mean([1, 2, 3, 4])).

Starter code

main.py
# load the statistics module
# print the mean of the list

Sample solution

main.py
import statistics
print(statistics.mean([1, 2, 3, 4]))

Expected output

2.5

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Complete the random module

Question 
import ____
print(random.randint(1, 6))
Answer 
import random
print(random.randint(1, 6))

Explanation: import random generates random numbers.

2 Which is in the standard library?

  • requests
  • numpy
  • pandas
  • math Correct answer

Explanation: math ships with Python; the others are third-party.

3 Match the standard library

Term Meaning
math Square root, pi
random Random number
datetime Date and time
statistics Mean, median

All lessons in Beginner

1 Python basics

  1. What is Python?
  2. REPL and print
  3. Comments
  4. Indentation blocks
  5. python -c and scripts
  6. Summary - Python basics

2 Variables

  1. Variable assignment
  2. Multiple assignment
  3. Naming variables
  4. id and type
  5. Swapping variables
  6. Summary - Variables

3 Data types

  1. int and float
  2. bool
  3. str basics
  4. None
  5. Type conversion
  6. Summary - Data types

4 Project: Calculator

  1. Project design
  2. Add/subtract
  3. Multiply/divide
  4. Error handling
  5. Putting it together

5 Operators

  1. Arithmetic
  2. Comparison
  3. Logical
  4. Bitwise
  5. Membership and identity
  6. Summary - Operators

6 String basics

  1. f-string
  2. Concatenation
  3. str.format
  4. Raw strings
  5. Triple-quote
  6. Summary - String basics

7 Conditionals

  1. The if statement
  2. elif and else
  3. Nested if
  4. Truthiness
  5. Conditional expression
  6. Summary - Conditionals

8 Loops

  1. The for loop
  2. range
  3. The while loop
  4. break and continue
  5. Loop else
  6. Summary - Loops

9 Project: Shopping cart

  1. Cart design
  2. Adding items
  3. Calculating totals
  4. Updating quantity
  5. Putting it together

10 Lists

  1. Declaring lists
  2. Index and slice
  3. List methods
  4. in and count
  5. Sorting lists
  6. Summary - Lists

11 List comprehension

  1. Comprehension basics
  2. Filtered comprehension
  3. Dict and set comprehension
  4. Nested comprehension
  5. Generator expression
  6. Summary - List comprehension

12 Tuple, set and dict

  1. Tuple
  2. Set
  3. Dict basics
  4. Dict methods
  5. Dict comprehension
  6. Summary - Tuple, set and dict

13 Functions

  1. def
  2. return
  3. Docstring
  4. Default parameters
  5. *args and **kwargs
  6. Summary - Functions

14 Function parameters

  1. Positional parameters
  2. Keyword parameters
  3. Keyword-only
  4. Positional-only
  5. Type hints basics
  6. Summary - Function parameters

15 Project: To-do CLI

  1. Task model
  2. Adding tasks
  3. Listing tasks
  4. Completing tasks
  5. Putting it together

16 Advanced string methods

  1. split and join
  2. strip, lstrip, rstrip
  3. replace
  4. find and index
  5. startswith, endswith
  6. Summary - Advanced strings

17 Input and output

  1. input()
  2. int/float conversion
  3. print parameters
  4. f-string formatting
  5. sys.argv
  6. Summary - Input and output

18 Error handling

  1. try/except
  2. else and finally
  3. raise
  4. Exception hierarchy
  5. Custom exceptions
  6. Summary - Error handling

19 Modules

  1. import
  2. from import
  3. as alias
  4. __name__ == '__main__'
  5. Standard library
  6. Summary - Modules

20 Beginner final

  1. Project design
  2. Data model
  3. Business logic
  4. Error handling
  5. Putting it together