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How to Extract and Access Data from JSON with PHP?

JSON (JavaScript Object Notation) is a popular data interchange format that is commonly used to transfer data between a server and a web application. In PHP, you can easily decode...

How to Reshape Data from Long to Wide Format in R

If you are working with data in R and need to reshape it from a long format to a wide format, then this article will guide you through the process. Reshaping data is often necessar...

Is storing a delimited list in a database column really that bad?

If you have ever worked with databases, you may have come across the scenario where you need to store multiple values in a single column. One common approach is to store these valu...

How can I fix 'android.os.NetworkOnMainThreadException'?

If you have encountered the 'android.os.NetworkOnMainThreadException' error while running your Android project, it means that you are attempting to perform a network operation on t...

Where and why do I have to put the "template" and "typename" keywords?

In C++ templates, the keywords "template" and "typename" are used to provide hints to the compiler in certain situations where it may not be able to deduce the correct meaning of a...

What is the scope of variables in JavaScript?

Variables in JavaScript have different scopes depending on how and where they are defined. The scope of a variable determines its accessibility and visibility throughout...

Can a local variable's memory be accessed outside its scope?

When writing code, one of the fundamental concepts to keep in mind is scoping. Scoping refers to the visibility and accessibility of variables within a program. In most programming...

How can I get query string values in JavaScript?

Retrieving query string values from a URL is a common task in web development. Query strings are the part of a URL that comes after the question mark (?) and can contain various pa...

Accessing an object property with a dynamically-computed name

In JavaScript, it is possible to access an object property with a dynamically-computed name. This can be useful when you want to access a property based on a variable value or a dy...

Why should I not #include <bits/stdc++.h>?

If you are a beginner in C++ programming, you might have come across the "#include <bits/stdc++.h>" directive in some code examples or tutorials. This directive is often reco...

What is the explicit promise construction antipattern and how do I avoid it?

The explicit promise construction antipattern, also known as the deferred antipattern or the Promise constructor antipattern, refers to the practice of using promise constructors s...

Is there a CSS parent selector?

When working with CSS, you may come across situations where you need to select a parent element based on its child element. However, CSS does not currently have a parent selector....

What are the basic rules and idioms for operator overloading?

Operator overloading is a powerful feature in C++ that allows you to redefine the behavior of an operator for user-defined types. It enables you to write code that is more expressi...

How do JavaScript Closures Work?

JavaScript closures are a powerful and often misunderstood concept. They allow you to create functions with persistent variables, preserving their state even after the function has...

How to Clone a List in Python to Avoid Unexpected Changes

In Python, lists are mutable objects, which means they can be modified after assignment. One common issue that developers face is that when they assign a list to a new variable usi...

What do querySelectorAll and getElementsBy* methods return?

When working with JavaScript and DOM manipulation, you may come across methods like getElementsByClassName, getElementsByTagName, and querySelectorAll. These methods are used to se...

"Least Astonishment" and the Mutable Default Argument

Python is a powerful and flexible programming language, but it can also have some unexpected behavior that can be confusing, especially for newcomers. One such issue is the behavio...

Pandas Merging 101

Merging basics - basic types of joins When working with pandas, merging DataFrames is a common operation that allows you to combine data from different sources based on common col...

How to Join (Merge) Data Frames in R: Inner, Outer, Left, and Right Joins

When working with data frames in R, it is often necessary to combine or merge them based on a common key. This process is similar to joining tables in SQL and allows you to combine...

Scanner is skipping nextLine() after using next() or nextFoo()?

If you have encountered a problem where the nextLine() method of the Scanner class is being skipped after using the next() or nextFoo() methods, you are not alone. This is a common...

How slicing in Python works

Python's slice notation allows you to extract a portion of a sequence, such as a list, string, or tuple. It provides a concise way to create sublists or substrings. I...

How does the "this" keyword work, and when should it be used?

Understanding the "this" keyword in JavaScript can be challenging for many developers, especially those who are new to the language. However, once you grasp the concept and learn h...

SQL injection that gets around mysql_real_escape_string()

SQL injection is a common security vulnerability where an attacker can manipulate SQL queries by inserting malicious code. It can allow unauthorized access to a database, modify da...

Understanding The Rule of Three in C++: Copy Constructor, Copy Assignment Operator, and Object Copying

When working with objects in C++, it is important to understand the concept of object copying. In some cases, you may need to create a copy of an existing object or p...

How to Solve mysqli_fetch_array() and Other MySQLi Problems

If you're encountering mysqli problems such as errors like "mysqli_fetch_array(): Argument #1 must be of type mysqli_result" or "Call to a member function bind_param(...