Tag: Python

Python – Writing a Logger in Python with a decorator

Functions in Python are objects. If this is the first time you read this sentence, then you will not get a lot from this article, but it will show you, that there is quite a lot to learn about Python.

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Python – DefaultDict Object. Or how to avoid the Key Error.

Have you seen the error below?

Of course you have. And you know, that it is because you have written something extremely unwise like this:

Yeah. You cannot increment the value of a non-existent key. Unless… Unless you

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VBA and Python – Intersection of dictionaries

Intersection of dictionary (or of any two lists) is a list with elements, that are present in both other lists. Thus, if we have the following 3 dictionaries in Python:

Then, an intersection of their keys will contain only

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Python – Class Variable vs Instance Variables

Class variables vs instance variables could seem a bit strange, if you have no OOP experience, but after a few thausand lines of code they become logical. So, in around two days of programming you will be getting it intuitively

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Python – Difference between __str__ and __repr__

__repr__  and __str__  dunders are quite similar in Python. If you need  a quick summary of these 2, then these 3 points will be enough: __repr__ dunder presents the class object, whenever it is called by the terminal __str__ dunder

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Json.dump vs json.dumps in Python

The difference between json.dump and json.dumps is actually quite visible: dump()  – dumps into a file or StringIO dumps()  – dumps a string, that could be printed Still, I am going to give a few example with these, as the

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Python – Iterators

One of the benefits of having your own blog and not following any schedule for subjects to write about is that you may write for whatever you feel like, whenever you feel like. So, Iterations in Python is the subject

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Django – CRUD application with Python

Making a CRUD application with Python is actually one of the basic thing a Python Developer should be able to do. Although some may argue it is extremely basic – it is not. Requirements The basic requirements for this one,

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Python – Exception handling

Exception handling in python is actually quite an interesting topic. In general, the exceptions in programming could be of three types: syntactic errors – these would be noticed by your IDE or by the interpretor, thus you do not need

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Using API calls with VBA and Python to Read and Write to a Database

Using API calls with VBA and Python to write a database is actually a pretty decent architecture. Here, I would like to say that “It takes the best of the both worlds”, but the truth is that it takes the

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Python – Django Girls – Introduction to Django – Video

Months ago, I was planning to take part in the #RailGirls event in Sofia, and I was even a partner in the event. Anyway, as it was postponed up to somewhere in the future, I have decided to go through

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Python – Writing Unit Tests with unittest library – Video

In the previous article for abstraction and inheritance I wrote some classes, showing the basics of these two programming concepts. In this one, I will write unit tests for one of the classes, written before. Software testing is an important

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Python – Abstraction and Inheritance – Video

Abstract classes in Python are classes that inherit from the ABC (Abstract base class). In the video below, I have solved a problem, showing how 2 classes inherit from an abstract class and implement its methods. The abstract class is

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Python – Closure

In this article I am planning to give an answer of the following two questions: What is a closure? A closure is a function, inheriting variables from enclosing environment. Operationally, a closure is a record storing a function together with

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Python – Abstract Methods and Abstract Class – Live Coding Video

Abstract class and abstract methods are one of the pillars of Object Oriented Programming. In Python, an abstract class is a class, inheriting from Abstract Base Classes (ABC) library. And an abstract method is a method of this class, which

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Python – Permutations and Combinations Made Easy with Itertools

Long time ago, various people, including me, were trying to make permutations and combinations with nested loops and various other “heavy” structures. Anyway, in Python there is a library, which does this for us and sets the end of the

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Python – Defining Classes and Methods with Python – LiveCoding Video

Today I have decided to check whether I can pass the first homework from SoftUni OOP with Python, through a live coding session. I have not read the problem before the video, thus I may say it took me exactly

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Python – Making Maps with Cartopy

Cartopy is a Python package designed for geospatial data processing in order to produce maps and other geospatial data analyses. Making a map with Python and Cartopy is actually easier than you might think, but still it has its own

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Python – Bayes’ theorem – Drug testing example. 99% is not enough!

The Bayes’ theorem is interesting, as far as it is both quite challenging to understand and shocking once you really realize the simplicity of the numbers behind it. It describes the probability of an event, based on prior knowledge of conditions that

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Python – Linear Regression

In 2013 and 2014 (wow, already 7 years ago!) I wrote two articles about linear regression with Excel. Now, I am getting more and more interested in Python, thus I guess it would be interesting to remake the article into

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Python – Building New Columns in a Dataframe, Based on Other Columns

Working with python, pandas and dataframes is quite challenging even for experienced Excel & VBA developer, as I love to consider myself for one. Thus, today I was fighting for quite some time to add new columns to a dataframe,

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Python – *args, **kwargs and the normal ones (arg)

The good, the bad and the ugly is a famous western. In Python, “the ugly” is probably the **kwargs, as far as it has two stars before it. Anyhow, the idea of *args, **kwargs and arg is simply to pass arguments.

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Python – List Comprehension

List comprehension in Python is creation of lists from iterables and other lists, following a condition. It is lightning fast and it looks nice, because it is a 1 liner. In this article, I will show a few examples of

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Python – What is the idea of “-1” in numpy reshape?

Today I was “fighting” with the numpy reshape function and I found something strange like matrix.reshape(1, -1). Thus, I have researched quite some time and I found, that the -1 is actually a placeholder for python to change the dimensions of

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Python – How to write string into a matrix. Printing a matrix.

Writing string into a matrix seems like a non-interesting and somehow trivial task. Anyway, manipulating with matrices and strings in Python is actually somehow interesting, thus I have decided to present a small algorithmic challenge.  The task is pretty much

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Python – UnitTests in Jupyter Notebook

Unit testing is the “sweet” part of the programming – once you have tested “all the things”, you feel that the code you have submitted somewhere is actually valid and somehow it works. Furthermore, it allows you to nicely brag

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Python – Statsmodels Example – Video

Statsmodels is a nice statistics library in Python, which eases the data processing and analysis with Python. The library is available here – statsmodels.org and on its official web site the installation guide is always up to date. In the

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Excel – How to build magic square with VBA, following Python Mod Mathematics

Some 4 years ago I wrote an article for calculating magic square with python. What the article did was actually checking whether the square is magic, and not calculating a new one. This one is going to show how these

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Python – Plotting DataFrame and Working with Pandas – Video

Working with Pandas is like working with Excel on steroids – it can really do a lot of things fast, but somehow doing the easy things get complicated. In this video and article tutorial I am presenting loading data to

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Cryptography in Python

ModernPythonStandardLibraryBook

After writing about hashing passwords in Python, I have decided to publish the other parts of the chapter, “Cryptography” from the “Modern Python Standard Library Cookbook“, written by Alessandro Molina and and kindly provided to me by PacktPublishing.In the article,

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