From basic functions to regular expressions
One essential task of programming is to get the data you need from a large amount of data. Searching certain substrings from strings is this type of task. If you happen to be a Python developer, congratulations! Because Python kindly gives us at least 3 options to do this job.
Of course, we can always use loops to go through characters one by one and find what we need. This article is not to discuss this brute force method. 🙂
This article will introduce the 3 common ways to search substrings, from the built-in functions( find() and index()) to regular…
Dive into the internal mechanisms
The memory management is one of the most popular interview topics for Python developers. Because questions about it can test a programmer’s understanding of some internal mechanisms of Python.
Some common questions are:
- How to get the memory address of a Python object (or vice versa)?
- How does Python collect garbage (useless objects)?
- How does Python optimise memory usages (interning mechanism)?
If you cannot answer the above questions clearly yet, no worries at all.
Because this article will explain them from elementary to profound. After reading, acing your tech interviews will be just a piece of cake. 🍰
Friendly Remind…
Choose the most appropriate one
A dictionary in Python, which contains key-value pairs, is one of the key data structures for daily programming. Besides the basic dict, Python kindly gives us more convenient options. Using them skillfully will make our code more elegant and our coding more smoothly.
This article will dive into 3 common used variants of Python dictionaries, from basic syntax to real scenarios. After reading, you will be able to choose the most appropriate one in real cases.
1. Defaultdict: Set a Default Value for Your Dict
When you get the value of a dict by a key, an unexpected exception may be raised:
>>> city = {'UK':'London','Japan':'Tokyo'}
>>> print(city['Italy'])#…
Although bugs are nearly inevitable in programming, senior developers can avoid lots of unnecessary bugs and write robust programs.
Why?
On the one hand, they made enough mistakes before thus they can avoid them in similar scenarios.
On the other hand, they are familiar with the programming language they are using, so they know where are the bug-prone points and how to deal with them.
This article will talk about 8 essential points to avoid bugs in Python programs based on my 8-year experience. Hope it’s useful.
0. Mind the Scope of Variables
The scope of Python variables is important but not intuitive for beginners. …
Do some magic in plain CSS
Nowadays, people have higher expectations for websites. To have all contents and functions users need is just the very basic requirement. A good website should be cool, or even awesome.
As we know, CSS, as a powerful tool, plays a key role for decorating a website. One of the best examples is that we can make animations just in plain CSS.
This article is a complete guide about CSS animations, from basic rules to precise manipulations. To help developers of any level understand CSS animations, the sample code and examples in this article are well-designed and easy to understand. …
Understand the web server gateway interface completely
Introduction to the WSGI
When we enter a link on a browser, what will happen?
Simply put, there are only four steps:
- The browser sends an HTTP request.
- The web server receives the request and finds or generates an HTML document.
- The server sends the HTML document as the body of a HTTP response to the browser.
- The browser receives the HTTP response, renders and displays the HTML document in it.
Therefore, to develop a website in Python, we just need to implement these four steps. Sounds easy? 🙂
However, parsing HTTP requests, sending HTTP responses and handling all the relative issues are complex…
Ace your algorithm interviews like a tech lead
To get a random number in Python is simple, since there is a built-in module called random. But how about weighted random numbers?
Let’s see a real interview question:
There is a dictionary as following:
my_nums = {'A': 5, 'B': 2, 'C': 2, 'D': 1}The keys are four letters and the values are their weights.
Please design a function that can generate a letter randomly based on the weights.
(In other words, this function should have 50% probability to generate “A”, 20% probability to generate “B”, 20% probability to generate “C”, and 10% probability to generate “D”.)
If you…
Algorithms change fast, but people don’t.
Dive into the string formatting technique in Python
The f-string, which was introduced by Python 3.6, is a simple and different string formatting technique to express Python strings elegantly.
Unless you are still using the old Python versions, the f-string should definitely be your preference when formatting strings. Because it can satisfy all your requirements by a minima syntax, and even run expressions in strings.
This article will dive into this technique from elementary to profound by 7 levels. After understanding them all, you probably will become a string formatting master.
1. Display Values From Variables Easily
There are only two things you need to do to use f-strings:
- Add an
fbefore the…
From simple methods to the ultimate weapon
Handling strings, especially messy strings, is the daily work of Python developers and data scientists. One of the most common symptoms of a messy string is that there are unnecessary or duplicate spaces in it.
Fortunately, no matter how messy a string is and how complicated a scenario is, Python can provide us a corresponding way to remove spaces as we like.
This article will introduce 5 different methods to remove spaces in a messy Python string based on different scenarios and requirements. After reading, you can choose the most appropriate way for your code. …
