We might also have a data set of Contacts
Might have a data set People that contains a unique numeric code for each person,įirst and last names, and birth dates. Need to squish them together to make a table with more columns. There are many cases where we have two or more data sets that are related and we Have a table Scores where each row represents a single assignment from a particular So the tidy version of the data would be to Times I’ve taught the course, the first option won’t work because sometimes IĪssign projects and sometimes not. However, if I was combining grade books from multiple An alternative representation would be for each rowĮither representation is fine in this case, because each student should have the In this case we are considering each row to represent a student and each variable In this representation,Įach row represents the information about a single. Students scores for four different homework assignments. Home a more challenging example, suppose we have grade book where we’ve stored Store the information with a single row representing a particular contact. Phone, work phone, cell phone, twitter handle, reddit user name, etc. Per person because then we’d need a column for work email, personal email, home However, because different people have severalĭifferent types of contact information, it would be a bad idea to have one row Suppose I have an address book where I keep email addresses, phone numbers, and Of storing the data in a messy (non-tidy) format. If your data has a large number of missing values, that is a symptom In particular I think that the attributes should be applicable to every single Noun and each now has multiple variables that adjectives that describe the noun. Often I like to think that the observations represent a The difficult part is recognizing what constitutes an observation and whatĬonstitutes a variable. Each table of data represents a different type of observational unit.I highly recommend reading Hadley Wickham’s introductionĭata is usually described as “tidy” if it satisfies the following: The terminology of “tidy data” popularized by Hadley Wickham and his introduction
Program, but it is useful to know the underlying file format and how to view it On aĭaily basis for viewing and editing the data, I’m happy to use my spread sheet See the raw file, you should specify to open it with a simple text editor. Open it with a spreadsheet program and again, not show the commas. If you open the file, the operating system will Typically your computer will show a preview of the file as if it were in spread The second row in the file is actually the first row of data, again With the first row of information being the column names, with each column separated In this case we see that the data is organized as you might see in an Excel file These files look like this: Student, HW1, HW2, HW3 One of the most common file formats we will encounter is the comma separated valuesįile, which has the file extension.
This is something that often happens in professional settings, but for thisĬourse, we’ll not worry about this situation.
Importing your data into your software is usually easy, and usually falls into 12.4.2 Florence Nightingale’s Rose Plot.12.4.1 John Snow’s Map of Cholera Outbreak.11.3.2 Miscellaneous Aggregation Levels.8.3.2 Pairs plots (All-vs-all scatterplots).8.2 Bivariate (one continuous, one categorical).6.2.4 Example - Federal Spending over Time.5.5 Creating Histograms, Boxplots, and Regression Lines.5.4 Selecting EPTs is done using the Marks pane.5.2 Light pre-processing and adjusting labels.