Extracting Key-Value Pairs from HTML Paragraphs: A Comparison of CSS Selectors and XPath Expressions
Introduction to Extracting Key-Value Pairs from HTML Paragraphs In this article, we will explore a way to extract key-value pairs from an HTML paragraph where keys are highlighted as <code>&lt;strong&gt;</code> elements. We’ll start with a discussion on the challenges of parsing such HTML and then dive into two different approaches: one using CSS selectors and another using XPath expressions. Challenges in Parsing HTML One of the main challenges when dealing with HTML is that there is no single element that corresponds to each key-value pair.
2025-04-03    
Analyzing and Visualizing Rolling ATR Sums in Pandas DataFrames with Python
import pandas as pd # create a DataFrame data = { 'id': [0, 1, 2, 3, 4, 360, 361, 362, 363, 364], 'time': [1620518400000, 1620604800000, 1620691200000, 1620777600000, 1620864000000, 1651622400000, 1651708800000, 1651795200000, 1651881600000, 1651968000000], 'open': [1.6206, 1.7662, 1.6418, 1.7633, 1.5669, 0.7712, 0.8986, 0.7884, 0.7832, 0.7605], 'high': [1.8330, 1.8243, 1.7791, 1.8210, 1.9719, 0.8992, 0.9058, 0.7997, 0.7858, 0.7663], 'low': [1.5726, 1.5170, 1.5954, 1.5462, 1.5000, 0.7677, 0.7716, 0.7625, 0.7467, 0.7254], 'close': [1.7663, 1.6423, 1.7632, 1.
2025-04-03    
Looping Through Columns and Adding Suffix to Respective Column Names Using Vectorized Operations and Iteration Number in R
Looping Through Columns and Adding Iteration Number to Respective Column Name Introduction In this article, we will explore how to loop through columns in a data frame and add a suffix to the column names based on an iteration number. We will discuss different approaches to achieve this goal, including using loops and vectorized operations. Understanding Data Frames and Column Names A data frame is a fundamental data structure in R, which is composed of rows and columns.
2025-04-03    
Iterating Through Column Names Across Two Data Frames in R Using a For Loop
Creating a for Loop in R to Iterate Through Column Names Across Two Data Frames Introduction In this article, we will explore how to create a for loop in R to iterate through a list of column names across two data frames and output match/no match for each sample. We will cover the necessary steps, including preparing the data, creating a list of loci, and implementing the for loop. Preparing the Data To begin with, let’s create two sample data frames, df1 and df2, which contain the same column names and data:
2025-04-03    
Understanding the Issue with Presenting View Controllers Outside of the Window Hierarchy
Understanding the Issue with Presenting View Controllers outside of the Window Hierarchy In iOS development, when you present a UIViewController or any other view controller, it is expected to be part of the window hierarchy. The window hierarchy refers to the sequence in which views are displayed on screen. In this context, we will delve into why presenting a view controller outside of this hierarchy results in an error. Why is Presenting Outside the Window Hierarchy a Problem?
2025-04-03    
Transforming Pivoted Data in SQL Server: A Step-by-Step Guide
Creating a Pivot of Same Columns into One Row in SQL Server In this article, we will explore how to create a pivot of the same columns into one row in SQL Server. This is often a challenging task, especially when dealing with dynamic data and multiple table relationships. Understanding the Problem The problem at hand involves transforming a dataset where each record has multiple fields, but some records share similar values for certain fields.
2025-04-03    
Extracting Historical S&P 500 Constituents Data with R and Web Scraping
Extracting S&P Symbols from Historical Data in R In this article, we will explore a way to extract the list of S&P 500 index constituents over the last N years using R. This involves web scraping and data manipulation. Introduction The S&P 500 is widely regarded as one of the most reliable stock market indexes in the world. However, obtaining historical data for individual stocks within this index can be challenging due to various reasons such as proprietary information, restricted access, or outdated sources.
2025-04-03    
How to Create Interactive Graphs in R Using External Tools Like Gnuplot
Introduction As a professional technical blogger, I’m excited to dive into the world of R scripting and explore ways to create interactive graphical devices using external tools like gnuplot. In this article, we’ll delve into the specifics of creating an interactive graph without relying on Sys.sleep, allowing for a more seamless user experience. Background For those new to R or its GUI capabilities, let’s briefly discuss what we’re working with here.
2025-04-02    
Comparing and Merging CSV Files Using Pandas: A Comprehensive Guide
Working with CSV Files: A Comprehensive Guide to Comparing and Merging Data When working with large datasets stored in Comma Separated Value (CSV) files, it’s essential to have the tools and techniques necessary to efficiently compare, merge, and manipulate data. In this article, we’ll delve into the world of pandas, a powerful library for data manipulation and analysis in Python. We’ll explore how to compare two CSV files based on their SKU numbers and write the result to a new CSV file.
2025-04-02    
Understanding Aspect Ratio in ggplot2 with geom_tile: 3 Essential Methods for Control and Consistency
Understanding Aspect Ratio in ggplot2 with geom_tile Introduction Aspect ratio is an essential concept in visualization, especially when working with data that needs to be represented in a two-dimensional format. In the context of ggplot2 and geom_tile, aspect ratio control is crucial for ensuring that the tiles are displayed correctly, regardless of whether the x-axis values are discrete or continuous. In this article, we will delve into the world of aspect ratio control in ggplot2, exploring both continuous and discrete axes scenarios.
2025-04-02