Lesser‑Known Python Standard Library Modules and Their Useful Functions

Python's standard library contains over 200 modules, many of which are underutilized; this article highlights several lesser‑known modules—difflib, sched, binascii, tty, and weakref—explaining their key functions and providing example code.

1. difflib

difflib

focuses on comparing data sets, especially strings. The most common functions include SequenceMatcher and get_close_matches.

SequenceMatcher

SequenceMatcher

compares two strings and returns a similarity ratio via ratio(). 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

get_close_matches

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

get_close_matches(word, possibilities, result_limit, min_similarity)

Example:

from difflib import get_close_matches

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

Other difflib utilities include unified_diff, Differ, and diff_bytes.

2. sched

sched

provides a platform‑independent event scheduler, typically used together with the time module.

Creating a scheduler instance:

schedular_name = sched.scheduler(time.time, time.sleep)

Key methods: run() – executes scheduled events in order. enterabs() – adds an event to the internal queue with parameters such as execution time, priority, function, arguments, and keyword arguments.

Example:

import sched, time

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

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

Additional functions include cancel(), enter(), and empty().

3. binascii

binascii

converts between binary data and ASCII representations. The b2a_base64 method encodes base64 data to binary.

Example:

import base64, 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

offers utilities for handling tty devices, primarily on Unix systems and often used with the termios module. setraw(fd) – sets the file descriptor to raw mode. setcbreak(fd) – sets the file descriptor to cbreak mode.

5. weakref

weakref

creates weak references to objects, allowing them to be garbage‑collected. getweakrefcount(obj) – returns the number of weak references to obj. getweakrefs(obj) – returns a list of weak references to obj.

Example:

import weakref

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

lotr = Book
num = 1
rcount_lotr = str(weakref.getweakrefcount(lotr))
rcount_num = str(weakref.getweakrefcount(num))
rlist_lotr = str(weakref.getweakrefs(lotr))
rlist_num = str(weakref.getweakrefs(num))
print("number of weakrefs of 'lotr': " + rcount_lotr)
print("number of weakrefs of 'num': " + rcount_num)
print("Weakrefs of 'lotr': " + rlist_lotr)
print("Weakrefs of 'num': " + rlist_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 utilities include ref(), proxy(), and _remove_dead_weakref().

Understanding these modules expands the Python toolbox, enabling more efficient and versatile code.