Webscraping using rvest Introduction Webscraping, also known as web scraping or web harvesting, is the process of automatically extracting data from websites. It can be used for a variety of purposes, such as data mining, market research, and automating tasks on the web. In this article, we will explore how to use Rvest, a popular R package for webscraping, to extract data from a specific website. Overview of rvest rvest is an R package that provides an easy-to-use interface for extracting data from HTML and XML documents.

Understanding the Problem and Requirements The problem at hand involves counting the frequency of values across rows in a dataset every 20 columns. This can be achieved by splitting the data into groups of 20 columns, then counting the occurrences of each value (0, 1, or 2) within these groups. Step 1: Data Preparation To start solving this problem, we need to prepare our dataset. The dataset should have a clear structure with each column representing a feature and rows representing individual observations.

Here is the code with comments and improvements: # Find column matches for price # Apply which to compare each row with the corresponding price in the "Price" column change <- apply(DF[, 3:62] == DF[,"Price"], 1, function(x) which(x)) # Update the "change" column for C # Multiply by -1 if the column matches DF$change[DF[,"C"]] <- change[DF[,"C"]] * (-1) # Find column matches for old price in preceding row if M pos2 <- apply(DF[which(DF[,"M"]) - 1, 3:62] == DF[,"Price"], 1, function(x) which(x)) # Update the "change" column for M # Subtract the position of the old price from the current price DF$change[DF[,"M"]] <- pos2[DF[,"M"]] - change[DF[,"M"]] # Print the updated "change" column print(DF$change) Note that I’ve also replaced apply(DF[, 3:62] == DF[,66], 1, which) with function(x) which(x) to make it more concise and readable.

Understanding UIDatePicker and Saving Selected Time ===================================================== In this article, we will explore how to make UIDatePicker display the user-selected time when the picker is opened again. Background UIDatePicker is a date picker control in iOS that allows users to select a specific date or time. By default, it displays the current date and time. However, by using certain properties and methods, we can customize its behavior and make it display the selected time when opened again.

String Formatting and Filtering for Numeric Comparison In this article, we’ll explore a technique for formatting and filtering strings to perform numeric comparisons. We’ll use the SQL Server programming language and its built-in string manipulation functions to achieve this goal. Introduction The problem at hand is to take a string in the format Nx:y, where x and y are integers of any length, and extract the file number (x) and the value (y).

Vector Filtering in R: A Deep Dive As a data analyst or programmer, working with vectors and lists is an essential part of your daily tasks. In this article, we’ll explore the concept of vector filtering in R and discuss various methods to achieve this goal. Introduction Vectors are a fundamental data structure in R, allowing you to store and manipulate collections of values. Filtering a vector involves selecting specific elements based on certain conditions.

Working with Time Zones in Pandas: Converting EST to Local Time Zone Info When working with time-stamped data, it’s essential to consider the time zone information. In this article, we’ll explore how to convert a timestamp column from Eastern Standard Time (EST) to its corresponding local time zone info available in another column using Python and the Pandas library. Introduction to Time Zones in Pandas Pandas is a powerful data analysis library that provides data structures and functions for efficiently handling structured data.

Subset DataFrame Based on Condition if Column Value Has String In this article, we will explore how to subset a pandas DataFrame based on conditions that involve strings. We will discuss the importance of string manipulation in data analysis and provide examples of different approaches to achieve this. Understanding the Problem The problem at hand involves filtering rows in a DataFrame where the column values meet certain conditions. In this case, we want to keep rows if, in a cluster of records, the column value starts with a specified string meeting two conditions.

Retrieving Top Values and Column Headers in a Row Using LINQ =========================================================== In this article, we’ll explore how to find the highest value in a row and return both the column header and its value. We’ll delve into the world of LINQ (Language Integrated Query) and provide a step-by-step guide on how to achieve this using various approaches. Background Before we dive into the solution, let’s briefly discuss the underlying concepts.

Animating View Transitions with UIViewAnimationTransitionFlipFromRight When developing iOS applications, one of the most common challenges developers face is navigating view transitions and animations. In this article, we will delve into a specific scenario where the UIViewAnimationTransitionFlipFromRight animation appears to be causing issues when adding a subview to another view in landscape mode. Introduction to UIViewAnimationTransitionFlipFromRight The UIViewAnimationTransitionFlipFromRight animation is designed to flip a view from one side of the screen to the other, typically used for transitioning between views or subviews.