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Alex Gebben Work 2025-09-15 17:43:46 -06:00
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@ -29,9 +29,9 @@
\begin{itemize}
\onslide<5->{\item \texttt{while(a==b)\{Code to run\}}}
\end{itemize}
\onslide<4->{apply functions }
\onslide<6->{\item apply functions }
\begin{itemize}
\onslide<5->{\item \texttt{while(a==b)\{Code to run\}}}
\onslide<7->{\item \texttt{while(a==b)\{Code to run\}}}
\end{itemize}
\end{enumerate}
\end{frame}
@ -43,7 +43,16 @@
\only<4>{\includegraphics[width=\textwidth]{apply_functions.png}}
\only<5>{\includegraphics[width=\textwidth]{sapply_loop.png}}
\end{frame}
\begin{frame}{Introduction}
\begin{frame}{Class Exercise}
\begin{itemize}
\item Create a loop that downloads a set of files when given a list of URLs.
\item Name each file based on another list.
\item Repeat for each type of loop (for, while, apply)
\end{itemize}
\end{frame}
\begin{frame}{Data transformation}
\begin{itemize}
\item Data rarely comes in the form you need.
\item Transformation helps prepare data for analysis and visualization.
@ -66,14 +75,7 @@
% Slide 3
\begin{frame}{Using the Pipe Operator}
\begin{itemize}
\item Pipe: \texttt{|>} passes output to next function
\item Example:
%\begin{verbatim}
%flights |>
% filter(dest == "IAH") |>
% group_by(year, month, day) |>
% summarize(arr_delay = mean(arr_delay, na.rm = TRUE))
% \end{verbatim}
\item Pipe: \texttt{|>} or \texttt{\%>\%} passes output to next function
\end{itemize}
\end{frame}
@ -103,9 +105,14 @@
\item Useful for aggregation and comparisons
\end{itemize}
\end{frame}
\begin{frame}[plain]
\only<1>{\includegraphics[width=\textwidth]{Pipe_Example.png}}
\only<2>{\includegraphics[width=0.8\textwidth]{Filter_Example.png}}
\only<3>{\includegraphics[width=\textwidth]{group_and Summarize.png}}
\end{frame}
% Slide 8
\begin{frame}{Class Example}
\begin{frame}{Class Exercise}
\textbf{Example:} dataset to apply dplyr: \texttt{airquality}
\begin{itemize}
@ -118,89 +125,4 @@
\item Use pipes to complete all tasks in one line
\end{itemize}
\end{frame}
\begin{frame}{Why Join Data?}
\begin{itemize}
\item Real-world data often comes in multiple tables.
\item Joins combine related data based on common keys.
\item \texttt{dplyr} provides intuitive functions for joining.
\end{itemize}
\end{frame}
% Slide 2
\begin{frame}{Types of Joins}
\begin{itemize}
\item \texttt{left\_join()} – keep all rows from left table
\item \texttt{right\_join()} – keep all rows from right table
\item \texttt{inner\_join()} – keep only matching rows
\item \texttt{full\_join()} – keep all rows from both tables
\end{itemize}
\end{frame}
% Slide 3
\begin{frame}{left\_join()}
\texttt{left\_join(df1, df2, by = "id")}
\begin{itemize}
\item Keeps all rows from the left table.
\item Adds matching rows from the right table.
\item Missing matches are filled with \texttt{NA}.
\end{itemize}
\end{frame}
% Slide 4
\begin{frame}{right\_join()}
\texttt{right\_join(df1, df2, by = "id")}
\begin{itemize}
\item Keeps all rows from the right table.
\item Adds matching rows from the left table.
\end{itemize}
\end{frame}
% Slide 5
\begin{frame}{inner\_join()}
\texttt{inner\_join(df1, df2, by = "id")}
\begin{itemize}
\item Keeps only rows with matching keys in both tables.
\item Most commonly used for filtering to shared data.
\end{itemize}
\end{frame}
% Slide 6
\begin{frame}{full\_join()}
\texttt{full\_join(df1, df2, by = "id")}
\begin{itemize}
\item Keeps all rows from both tables.
\item Missing matches are filled with \texttt{NA}.
\end{itemize}
\end{frame}
% Slide 7
\begin{frame}{Common Issues}
\begin{itemize}
\item Mismatched column names
\item Duplicate keys – can lead to unexpected row duplication
\item Data types must match, both keys should be character or numeric
\item Missing value joins will introduce \texttt{NA}s
\end{itemize}
\end{frame}
% Slide 8
\begin{frame}{Best Practices}
\begin{itemize}
\item Inspect keys before joining: \texttt{unique()}
\item Use \texttt{anti\_join()} to find unmatched rows
\item Validate results with \texttt{summary()} and \texttt{count()}
\end{itemize}
\end{frame}
% Slide 9
\begin{frame}{Class Exercise}
\begin{itemize}
\item Joins are essential for combining data.
\item Choose the right join based on your goal.
\item Always check for common issues before and after joining.
\end{itemize}
\end{frame}
\end{document}