select

Hi David, I'm trying to figure out the keyboard shortcut to run code - for Macs, it says up arrow + Command + and another arrow I cannot figure out. What is that exactly? Thanks!

Is it possible to 'select' from a row rather than a column? Or does wrangling data in R require data frames to be vertical?

How do you accommodate using the 'select' function if your table headers are merged?

FYI to the group I was looking for the pipe shortcut reminder and came across this link: https://support.rstudio.com/hc/en-us/articles/200711853-Keyboard-Shortcuts

Also a note for what's worked for me on 'select' section: when I try the suggested code format such as "marital_status", I get an error; but when I format identically to the imported nhanes dataset, "MaritalStatus" works (matches variable name). Same throughout the exercise.

Is there an output that tells us all of our columns? I have the parsing notice but that doesn't show all the columns so I am not sure how to do the "select variables from 'health_gen' to end' without looking at the solutions.

Comment rather than a question. When dropping a range of variables, I tired this code: select(-heath_gen:education), which left out a set of parentheses. One solution is to include the parentheses, so the code is select(-(heath_gen:education)). However, I found that this also works: select(-heath_gen:-education).

None of the exercises that are evident in your tutorial video are accessible to me in the data-wrangling-and-analysis-exercises RMD file. I just have the code you used.

Hi David,

Any quick way to select a column to the last column? E.g health_gen to the last column, instead of typing out select(health_gen:smoke_now]?

Nothing major, but I've noticed that several of the variable names differ between your solutions video and my nhanes (e.g., Height vs height and HealthGen vs. health_gen).

It may be another issue of things changing slightly in the data over time. But it has served as good reminder to be careful about capitalization (and why to avoid it in variable names)

Thanks for the help. But I don't think that's my issue.

nhanes % select(marital_status)

##I get the error: "Error: Can't subset columns that don't exist. x Column marital_status doesn't exist. Run rlang::last_error() to see where the error occurred." But using the original variable name MaritalStatus, the code runs fine.

Hi David!

I ran clean_names on nhanes and then displayed nhanes to see if it worked - it did. However, when I move on to the select function, it refuses to recognized the cleaned version and still refers to the earlier version. Is there something I missed?

Thanks!

Im getting an error "attempt to use zero-length variable name" when I use the following code:

nhanes %>% 
  select(marital_status, education)

Any idea what the error message means? It worked for the single select.

Just reflecting on the data wrangling - it looks like the data on the excel (or CSV) sheet has to be set up just right to be able to use these coding exercises. Can you share more about the data file preparation? What practices we should have in place regarding variables, types of inputted data, etc? A lot of my time is spent in data cleaning before actually getting to the analyses. Sorry if I am getting ahead !

Could you please go over the use of "quotes" around a term. When are quotes required, and when are they not necessary? For example, quotes are used here - select(contains("hlth_bad")). But no quotes are used here - select(marital_status, education). Thanks!

I believe I'm having the same issue as described by Matt M below. I have run the clean_names function and I get an output with the new correct names. However when I run the select functions if I don't put in the previous names I get an error message that says the columns don't exist. If I put in the non-cleaned names it works fine. I see that you have a video below, but I get a message that I don't have permission to view the video. Could you let me know what the solution was?