travis build failing because devtools is missing Introduction to Travis CI and R Package Development Travis CI is a popular continuous integration platform used by many developers and organizations to automate the testing of their software projects. In this article, we will focus on setting up a Travis CI build for an R package using the devtools package. Background: Installing devtools Manually The first issue that arises when trying to install the devtools package in a Travis CI build is related to its dependencies.

Converting String to Dates where Month and/or Day is Missing Introduction In data analysis and manipulation, working with dates can be a challenge, especially when the date string is incomplete. In this article, we will explore how to convert string to dates in R when the month and/or day are missing. Why Use lubridate? lubridate is a popular package for date and time manipulation in R. It provides a set of useful functions for working with dates, including parsing incomplete date strings into complete date objects.

Creating a MultiIndex DataFrame in Pandas for Customized String Retrieval In this blog post, we’ll delve into the world of Pandas DataFrames and explore how to create a MultiIndex DataFrame that allows us to separate headers by country and region. We’ll use this technique to retrieve specific columns from our DataFrame based on a given string. Introduction to Pandas DataFrames A Pandas DataFrame is a two-dimensional data structure with rows and columns, similar to an Excel spreadsheet or a table in a relational database.

Understanding Core Data: Exploring Core Data Tables and Deleting Data on Real Devices Core Data is a powerful framework for managing model data in iOS, macOS, watchOS, and tvOS apps. It provides an object-relational mapping (ORM) system that allows developers to interact with their app’s data using familiar Cocoa classes. However, one common question that arises when working with Core Data is how to access or delete the underlying database tables stored on a real device.

Understanding Scatter Plots and Axis Ordering in Plotly Introduction Plotly is a popular data visualization library that allows users to create interactive and engaging visualizations. One of the key features of Plotly is its ability to customize the appearance of plots, including axis ordering. In this article, we will explore how to sort the x-axis in a scatter chart using Plotly. Background Before diving into the solution, let’s take a look at some background information on scatter plots and axis ordering.

Understanding the c() Function in R: A Deep Dive into Vectorized Operations The c() function in R is a fundamental component of programming, allowing users to combine vectors and create new ones. However, its behavior can be cryptic, especially when dealing with complex operations like logarithms and conditional statements. In this article, we’ll delve into the world of c() and explore why it takes two vectors as input and outputs one.

Pandas Computing Groupby Stats based on Rows of Multiple Null Columns =========================================================== In this article, we will explore how to compute mean and standard deviation (std) for groups in a DataFrame where at least one column contains null values. We will cover the approach using conditional filtering and then discuss alternative approaches. Problem Statement Given a DataFrame mdf with columns ‘ST’, ‘LW’, ‘UD’, ‘v1’ and null values, we want to calculate mean and std for groups where both ‘mean’ and ‘std’ columns are null.

Understanding Recursive Functions in PHP and MySQL In this article, we will explore how to traverse all rows in a column using PHP. This involves understanding recursive functions, their application in solving complex problems, and their implementation using PHP. Introduction Recursive functions are a powerful tool for solving complex problems. A function is said to be recursive if it calls itself as part of its execution. Recursive functions have two main characteristics: they must have a base case and a recursive case.

Understanding DataFrames in Python =============== DataFrames are two-dimensional data structures with labeled columns and rows. They provide a convenient way to work with structured data, similar to how tables do in databases. In this blog post, we will explore the concept of DataFrames, their construction, and manipulation using popular libraries such as pandas. Introduction to Pandas Pandas is a powerful Python library used for data manipulation and analysis. It provides data structures and functions designed to make working with structured data easier.

Introduction to Extracting Average Numbers from Character Strings in R R is a powerful programming language and environment for statistical computing and graphics. One of the common tasks in data analysis is working with character strings that contain numerical values, which can be challenging to process. In this article, we will discuss how to extract average numbers from a character string in R. Understanding the Problem The problem presented in the question is quite common in data analysis.