5 Little‑Known Python Standard Library Modules You Should Use

Python's standard library contains over 200 modules, many of which are under‑used despite offering useful functionality for a wide range of tasks. This article highlights five lesser‑known modules and demonstrates how to apply their most common functions.

1. difflib

difflib

focuses on comparing data sets, especially strings. The most frequently used functions are:

SequenceMatcher – compares two strings and returns a similarity ratio via ratio(), which quantifies similarity as a percentage.

Syntax: SequenceMatcher(None, string1, string2) Example:

from difflib import SequenceMatcher
phrase1 = "Tandrew loves Trees."
phrase2 = "Tandrew loves to mount Trees."
similarity = SequenceMatcher(None, phrase1, phrase2)
print(similarity.ratio())  # Output: 0.8163265306122449

get_close_matches returns the closest matches to a given word from a list of possibilities.

Syntax:

get_close_matches(word, possibilities, result_limit, min_similarity)

Parameters: word – the target word to match. possibilities – a list of candidate strings. result_limit – optional limit on the number of results. min_similarity – optional minimum similarity threshold.

Example:

from difflib import get_close_matches
word = 'Tandrew'
possibilities = ['Andrew', 'Teresa', 'Kairu', 'Janderson', 'Drew']
print(get_close_matches(word, possibilities))  # Output: ['Andrew']

Additional useful functions in difflib include unified_diff, Differ, and diff_bytes.

2. sched

sched

provides a cross‑platform event scheduler, often used together with the time module.

Typical usage involves creating a scheduler instance and scheduling events with enterabs() or enter(), then running the scheduler with run().

Example:

import sched
import time

def event_notification(event_name):
    print(event_name + " has started")

my_sched = sched.scheduler(time.time, time.sleep)
my_sched.enterabs(time.time(), 1, event_notification, ("The Closing Ceremony",))
my_sched.run()  # Output: The Closing Ceremony has started

Other useful sched functions include cancel(), enter(), and empty().

3. binaascii

binascii

offers utilities for converting between binary data and ASCII representations.

Key function b2a_base64 converts binary data to a base64‑encoded ASCII string.

Example:

import base64
import binascii
msg = "Tandrew"
encoded = msg.encode('ascii')
base64_msg = base64.b64encode(encoded)
decode = binascii.a2b_base64(base64_msg)
print(decode)  # Output: b'Tandrew'

Other functions include a2b_qp(), b2a_qp(), and a2b_uu().

4. tty

tty

contains utility functions for handling terminal devices. Two common functions are: setraw(fd) – puts the file descriptor into raw mode. setcbreak(fd) – puts the file descriptor into cbreak mode.

These functions require the termios module and are only available on Unix‑like systems.

5. weakref

weakref

enables the creation of weak references to objects, which do not prevent garbage collection.

Important functions: getweakrefcount(obj) – returns the number of weak references to obj. getweakrefs(obj) – returns a list of all weak references to obj.

Example:

import weakref
class Book:
    def print_type(self):
        print("Book")

lotr = Book
num = 1
print("number of weakrefs of 'lotr': " + str(weakref.getweakrefcount(lotr)))
print("number of weakrefs of 'num': " + str(weakref.getweakrefcount(num)))
print("Weakrefs of 'lotr': " + str(weakref.getweakrefs(lotr)))
print("Weakrefs of 'num': " + str(weakref.getweakrefs(num)))
# Output:
# number of weakrefs of 'lotr': 1
# number of weakrefs of 'num': 0
# Weakrefs of 'lotr': [<weakref at 0x...; to 'type' ... (Book)>]
# Weakrefs of 'num': []

Additional functions include ref(), proxy(), and _remove_dead_weakref().

Review

difflib

provides powerful string comparison tools such as SequenceMatcher and get_close_matches. sched works with time to schedule events via a scheduler instance, using enterabs() and run(). binascii converts between binary and ASCII, with b2a_base64 handling base64 encoding. tty offers terminal handling functions that require termios and are Unix‑specific. weakref manages weak references, allowing inspection of reference counts and retrieval of existing weak references.

Key Takeaways

Each of these modules serves a distinct purpose and can be highly useful in the right context. Expanding your knowledge of Python's built‑in modules helps you build a more stable toolbox and write code more efficiently.

Regardless of your current expertise, investing time to explore these modules will add value to your projects and save you time in the future.