rnw | React and Node workshop : Building a mini-Spotify MusicHub | Frontend Framework library

I am new to Shiny and it really gives me headaches this problem. I have made a Shiny app where you upload an excel, set some variables and then makes some statistical test on that variables( first a regression model then model assumption). I need to export a pdf file which contains the outputs of the regression model and the statistical test along with the conclusions of the tests.

I am using knit2pdf and this is my code: Server:

I have problem with running my .rnw (I am running Sweave) files in RStudio due to this error message:

I use Sweave (Rnw) questions using exams2moodle() from R/exams. All works fine except when I'm trying to use dropdown question for schoice or mchoice questions. Following the manual I try to use the option cloze_mchoice_display = "MULTICHOICE", but that does not work.

I include an example Rnw exercise along with my R code below.

I'm building on the deriv2.Rnw question from the r-exams package, which includes num_to_schoice to randomize the answer options of a schoice question:

Motivation: I want to write an interface that uses questions from the R package exams in learnr questions/quizzes. In R/exams each question is either an R/Markdown (Rmd) or R/LaTeX (Rnw) file with a certain structure specifying question, solution, and further meta-information. The questions can contain R code to make them dynamic, e.g., sampling numbers or certain text building blocks etc. Hence, the workflow is that first the questions are run through knitr::knit or utils::Sweave and then embedded in a suitable output format.

Problem: When I rmarkdown::run("learnr+rexams.Rmd") a learnr tutorial that dynamically produces a question or quiz from an Rmd exercise I get the error:

Error in if (grepl(not_valid_char_regex, label)) { : argument is of length zero

The code for a simple reproducible example learnr+rexams.Rmd is included below. The reason for the error appears to be that learnr runs a function verify_tutorial_chunk_label() that tries to assure the the learnr R chunk labels are well formatted. However, confusion is caused by the chunks that are run by the R/exams package, unnecessarily leading to the error above.

Workarounds: I can disable the verify_tutorial_chunk_label() in the learnr namespace and then everything works well. Or I can use Rnw instead of Rmd exercises and then learnr does not conflict with Sweave(). Also, when I run my code outside of a learnr tutorial it works fine.

Question: Can I do anything less invasive to make exams cooperate with learnr? For example, setting some appropriate knitr options or something like that?

Example: This is the source for the minimal learnr tutorial learnr+rexams.Rmd that replicates the problem. Note that everything is very much simplified and only works for certain R/exams exercises, here using the function exercise template that ships with R/exams.

Basically, I want to totally disable API access for all user other than sysadmins (v2.9.1).

1. Where in the code can I see the logic related to this? Closest I could find was via

In the great R-exams package can specify the numerical answers width in cloze questions with \exextra[numwidth,logical]{TRUE}.

I want create exams with mixed type cloze, for example num|num|string (solve an equation and don't know how many solutions exist - if less than three, the latest answers should be -). In this case the answers fields appear like this:

The students know the last answer is string because this input box is smaller than other. How can all input boxes be equal width?

(I want import the output into Moodle so this question maybe exams2moodle()-specific.)

MWE:

I started working on this project a little over a year ago, and it seems a file is missing from what may be even longer than that. I am trying to go back into my repo to find when this file may have been removed but I do not know what commit let alone the date or user who may have done it.

It seem that in Azure Devops I can only search by name, path, user, date, or by just going thru every commit ever until I find the file lol. I have gone thru the history of the file that contains it but again without knowledge of the date or user or commit, I have no way to find it?

I have tried git commands, something along the lines of

This seems like a simple problem, but I wasn't able to find a solution anywhere I looked.

I am writing a .Rnw document in R with the Knitr package, one that I intend to compile into .pdf form by the end. I want it to contain a few plots, preferably ones made with the ggplot2 package because it seems like the simplest solution. However, I cannot force R to include a plot in the final document. Instead of a graphic, the code writes "list()" in the place the plot should be at. Am I missing a package? Am I writing something wrong? Here is the relevant part of the code: