The Difference Between __str__ and __repr__

__str__ and __repr__ are used in very similar ways in Python, but they’re not interchangeable. __str__ is a built in function used to compute the informal string representations of an object, while __repr__ must be used to compute the official string representations of an object. The visible difference between the informal and official representations has […]

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Python Comparison Operators

In Python, comparison operators are used to compare the values on either side of the operators and then decide the relationship between them (sometimes they’re also referred to as relational operators). What follows is a complete list of the comparison operators in Python. Some of them might be pretty self-explanatory, while others you may have […]

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Python’s null equivalent: None

What is the null or None Keyword The null keyword is commonly used in many programming languages, such as Java, C++, C# and Javascript. It is a value that is assigned to a variable. Perhaps you have seen something like this: null in Javascript

null in PHP

null in Java

The concept […]

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Memory-Mapped (mmap) File Support in Python

What is a Memory-Mapped File in Python From Python’s official documentation, be sure to checkout Python’s mmap module: A memory-mapped file object behaves like both strings and like file objects. Unlike normal string objects, however, these are mutable. Basically, a memory-mapped (using Python’s mmap module) file object maps a normal file object into memory. This […]

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PySide/PyQt Tutorial: QWebView

The QWebView is a highly useful control; it allows you to display web pages from URLs, arbitrary HTML, XML with XSLT stylesheets, web pages constructed as QWebPages, and other data whose MIME types it knows how to interpret. It uses the WebKit web browser engine. WebKit is an up-to-date, standards-compliant rendering engine used by Google’s […]

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Writing Your First Python Django Application

Create A Django Project The previous article Introduction to Python’s Django presented an overview of the Django Framework. In this article, we are going to write a simple Django application from scratch. The first step is to create a project using one of Django’s built-in commands In a Virtualenv, type this command: […]

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Lambda Function Syntax (Inline Functions) in Python

Python’s syntax is relatively convenient and easy to work with, but aside from the basic structure of the language Python is also sprinkled with small syntax structures that make certain tasks especially convenient. The lambda keyword/function construct is one of these, where the creators call it “syntactical candy”. Here we’ll examine how to use them. To understand the lambda keyword/function and their […]

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Catching Python Exceptions – The try/except/else keywords

Often times when coding a python masterpiece, there are certain things that could go wrong when executing your masterfully designed code. Things such as files or directories that are missing, empty strings, variables that are supposed to be strings but are actually arrays at run-time. These things are called exceptions in Python. This is what […]

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PySide/PyQT Tutorial: QListView and QStandardItemModel

In our last instalment, we discussed Qt’s QListWidget class, which allows the user to make simple single-column list boxes. For more advanced list controls, however, a more flexible widget is required; for that reason, Qt supplies the QListView widget, which allows more varied items to be created. It is a pure presentation widget, which displays […]

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Cutting and Slicing Strings in Python

Python Strings as Sequences of Characters Python strings are sequences of individual characters, and share their basic methods of access with those other Python sequences – lists and tuples. The simplest way of extracting single characters from strings (and individual members from any sequence) is to unpack them into corresponding variables.

Unfortunately, it’s not […]

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