Table of contents

foreword

The Python standard library has over 200 modules that programmers can import and use in their programs. While the average programmer has some experience with many of these modules, there are likely some useful ones they still haven't noticed.

I've found that many of these modules contain functions that are useful in various fields. Comparing datasets, collaborating with other functions, and audio processing can all be automated using only Python.

1. difflib

difflib is a Python module focused on comparing datasets , especially strings. To get a concrete idea of a few things you can do with this module, let's examine some of its most common functions.

SequenceMatcher

SequenceMatcher is a function that compares two strings and returns data based on their similarity. By using ratio(), we will be able to quantify this similarity in terms of ratios/percentages .

grammar:

SequenceMatcher(None, string1, string2)

The following simple example shows the function in action:

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

Next get_close_matches, the function returns the closest match to the string passed in as a parameter.

grammar:

get_close_matches(word, possibilities, result_limit, min_similarity)

Here's an explanation of these potentially confusing parameters:

word is the target word the function will look at.
possibilities is an array containing the matches the function will look for and find the closest match.
result_limit is the limit on the number of returned results (optional).
min_similarity is the minimum similarity two words need to have to be considered a return value by the function (optional).

Here is an example of its use:

from difflib import get_close_matches

word = 'Tandrew'
possibilities = ['Andrew', 'Teresa', 'Kairu', 'Janderson', 'Drew']

print(get_close_matches(word, possibilities))
# Output: ['Andrew']

There are a few Difflib other methods and classes that you can look at that belong to: unified_diff, Differand diff_bytes

2. sched

sched is a useful module centered around event scheduling that works across platforms, in stark contrast to tools like Task Scheduler on Windows. Most of the time when using this module, you will use schedular classes.

The more common time modules are often sched used together with , since they both deal with the concepts of time and scheduling.

Create an schedular instance:

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

Various methods can be called from this instance.

When called run() , the events/entries in the scheduler are called in order. This function usually appears at the end of the program, after scheduling events. In addition, search for the official account Linux and learn how to reply to "git books" in the background to get a surprise gift package.
enterabs() is a function that essentially adds the event to the scheduler's internal queue. It receives several parameters in the following order:
- time the event was executed
- activity priority
- the event itself (a function)
- Parameters of the event function
- A dictionary of keyword arguments for the event

Here's an example of how to use these two functions together:

import sched
import 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

There are also several sched functions that extend the usage of the module: cancel(), , enter() and empty().

3. Binascii

binaascii is a module for converting between binary and ASCII.

b2a_base64 is binaascii a method in the module that converts base64 data to binary data. Here is an example of this method:

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'

This code should be self-explanatory. Simply put, it involves encoding, converting to base64, and using b2a_base64 methods to convert it back to binary.

Here are binaascii some other functions that belong to the module: a2b_qp(), , b2a_qp() and a2b_uu().

4. tty

tty is a module containing several utility functions for working with tty devices. Here are its two functions:

setraw() Changes the mode of the file descriptor in its argument (fd) to raw.
setcbreak() Changes the mode of the file descriptor in its argument (fd) to cbreak.

This module is only available on Unix due to the need to use termios modules, such as specifying the second parameter ( ) in the above two functions when=termios.TCSAFLUSH.

5. weakref

weakrefis a module for creating weak references to objects in Python .

Weak references are references that do not protect a given object from being collected by garbage collection mechanisms.

The following are the two functions associated with this module:

getweakrefcount() Takes an object as a parameter and returns the number of weak references that refer to that object.
getweakrefs() Takes an object and returns an array containing all weak references that refer to that object.

weakref Example usage of its functions:

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 0x10b978a90; to 'type' at #0x7fb7755069f0 (Book)>]
# Weakrefs of 'num': []

Output From the output function return value we can see what it does. Since num there are no weak references, getweakrefs() the returned array is empty.

Here are weakref some other functions related to the module: ref(), , proxy() and _remove_dead_weakref().

Summarize

Each of these functions has its own purpose, and each has varying degrees of usefulness. It's important to know as many Python functions and modules as possible in order to maintain a stable library of tools that you can use quickly as you write code.

[Unpopular but easy to use] Recommended Python library