R exams package weird behaviour with dplyr












1















I have noted to strange behaviour in the R exams package when I load the dplyr library. the below example only works if I explicitly call the dplyr namespace, as indicated in the comments. notice that the error only occurs in a fresh session, i.e. you need to restart R in order to see what I see. You need to place the below in a file exam.Rmd, then call



library(exams)
library(dplyr)
exams2html("exam.Rmd") # in pwd

# this is exam.Rmd
```{r datagen,echo=FALSE,results='hide',warning=FALSE,message=FALSE}
df = data.frame(i = 1:4, y = 1:4, group = paste0("g",rep(1:2,2)))
# works:
b2 = diff(dplyr::filter(df,group!="g1")$y)
b3 = diff(dplyr::filter(df,group!="g2")$y)
# messes up the complete exercise:
# b2 = diff(filter(df,group!="g1")$y)
# b3 = diff(filter(df,group!="g2")$y)
nq = 2
questions <- solutions <- explanations <- rep(list(""), nq)
type <- rep(list("num"),nq)

questions[[1]] = "What is the value of $b_2$ rounded to 3 digits?"
questions[[2]] = "What is the value of $b_3$ rounded to 3 digits?"
solutions[[1]] = b2
solutions[[2]] = b3
explanations[[1]] = paste("You have you substract the conditional mean of group 2 from the reference group 1. gives:",b2)
explanations[[2]] = paste("You have you substract the conditional mean of group 3 from the reference group 1",b3)
```


Question
========
You are given the following dataset on two variables `y` and `group`.

```{r showdata,echo=FALSE}
# kable(df,row.names = FALSE,align = "c")
df
```

some text with math

$y_i = b_0 + b_2 g_{2,i} + b_3 g_{3,i} + e_i$

```{r questionlist, echo = FALSE, results = "asis"}
answerlist(unlist(questions), markup = "markdown")
```

Solution
========

```{r sollist, echo = FALSE, results = "asis"}
answerlist(unlist(explanations), markup = "markdown")
```

Meta-information
================
extype: cloze
exsolution: `r paste(solutions,collapse = "|")`
exclozetype: `r paste(type, collapse = "|")`
exname: Dummy Manual computation
extol: 0.001









share|improve this question


















  • 2





    Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

    – hrbrmstr
    Nov 21 '18 at 15:00













  • @hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

    – Florian Oswald
    Nov 22 '18 at 8:33
















1















I have noted to strange behaviour in the R exams package when I load the dplyr library. the below example only works if I explicitly call the dplyr namespace, as indicated in the comments. notice that the error only occurs in a fresh session, i.e. you need to restart R in order to see what I see. You need to place the below in a file exam.Rmd, then call



library(exams)
library(dplyr)
exams2html("exam.Rmd") # in pwd

# this is exam.Rmd
```{r datagen,echo=FALSE,results='hide',warning=FALSE,message=FALSE}
df = data.frame(i = 1:4, y = 1:4, group = paste0("g",rep(1:2,2)))
# works:
b2 = diff(dplyr::filter(df,group!="g1")$y)
b3 = diff(dplyr::filter(df,group!="g2")$y)
# messes up the complete exercise:
# b2 = diff(filter(df,group!="g1")$y)
# b3 = diff(filter(df,group!="g2")$y)
nq = 2
questions <- solutions <- explanations <- rep(list(""), nq)
type <- rep(list("num"),nq)

questions[[1]] = "What is the value of $b_2$ rounded to 3 digits?"
questions[[2]] = "What is the value of $b_3$ rounded to 3 digits?"
solutions[[1]] = b2
solutions[[2]] = b3
explanations[[1]] = paste("You have you substract the conditional mean of group 2 from the reference group 1. gives:",b2)
explanations[[2]] = paste("You have you substract the conditional mean of group 3 from the reference group 1",b3)
```


Question
========
You are given the following dataset on two variables `y` and `group`.

```{r showdata,echo=FALSE}
# kable(df,row.names = FALSE,align = "c")
df
```

some text with math

$y_i = b_0 + b_2 g_{2,i} + b_3 g_{3,i} + e_i$

```{r questionlist, echo = FALSE, results = "asis"}
answerlist(unlist(questions), markup = "markdown")
```

Solution
========

```{r sollist, echo = FALSE, results = "asis"}
answerlist(unlist(explanations), markup = "markdown")
```

Meta-information
================
extype: cloze
exsolution: `r paste(solutions,collapse = "|")`
exclozetype: `r paste(type, collapse = "|")`
exname: Dummy Manual computation
extol: 0.001









share|improve this question


















  • 2





    Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

    – hrbrmstr
    Nov 21 '18 at 15:00













  • @hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

    – Florian Oswald
    Nov 22 '18 at 8:33














1












1








1








I have noted to strange behaviour in the R exams package when I load the dplyr library. the below example only works if I explicitly call the dplyr namespace, as indicated in the comments. notice that the error only occurs in a fresh session, i.e. you need to restart R in order to see what I see. You need to place the below in a file exam.Rmd, then call



library(exams)
library(dplyr)
exams2html("exam.Rmd") # in pwd

# this is exam.Rmd
```{r datagen,echo=FALSE,results='hide',warning=FALSE,message=FALSE}
df = data.frame(i = 1:4, y = 1:4, group = paste0("g",rep(1:2,2)))
# works:
b2 = diff(dplyr::filter(df,group!="g1")$y)
b3 = diff(dplyr::filter(df,group!="g2")$y)
# messes up the complete exercise:
# b2 = diff(filter(df,group!="g1")$y)
# b3 = diff(filter(df,group!="g2")$y)
nq = 2
questions <- solutions <- explanations <- rep(list(""), nq)
type <- rep(list("num"),nq)

questions[[1]] = "What is the value of $b_2$ rounded to 3 digits?"
questions[[2]] = "What is the value of $b_3$ rounded to 3 digits?"
solutions[[1]] = b2
solutions[[2]] = b3
explanations[[1]] = paste("You have you substract the conditional mean of group 2 from the reference group 1. gives:",b2)
explanations[[2]] = paste("You have you substract the conditional mean of group 3 from the reference group 1",b3)
```


Question
========
You are given the following dataset on two variables `y` and `group`.

```{r showdata,echo=FALSE}
# kable(df,row.names = FALSE,align = "c")
df
```

some text with math

$y_i = b_0 + b_2 g_{2,i} + b_3 g_{3,i} + e_i$

```{r questionlist, echo = FALSE, results = "asis"}
answerlist(unlist(questions), markup = "markdown")
```

Solution
========

```{r sollist, echo = FALSE, results = "asis"}
answerlist(unlist(explanations), markup = "markdown")
```

Meta-information
================
extype: cloze
exsolution: `r paste(solutions,collapse = "|")`
exclozetype: `r paste(type, collapse = "|")`
exname: Dummy Manual computation
extol: 0.001









share|improve this question














I have noted to strange behaviour in the R exams package when I load the dplyr library. the below example only works if I explicitly call the dplyr namespace, as indicated in the comments. notice that the error only occurs in a fresh session, i.e. you need to restart R in order to see what I see. You need to place the below in a file exam.Rmd, then call



library(exams)
library(dplyr)
exams2html("exam.Rmd") # in pwd

# this is exam.Rmd
```{r datagen,echo=FALSE,results='hide',warning=FALSE,message=FALSE}
df = data.frame(i = 1:4, y = 1:4, group = paste0("g",rep(1:2,2)))
# works:
b2 = diff(dplyr::filter(df,group!="g1")$y)
b3 = diff(dplyr::filter(df,group!="g2")$y)
# messes up the complete exercise:
# b2 = diff(filter(df,group!="g1")$y)
# b3 = diff(filter(df,group!="g2")$y)
nq = 2
questions <- solutions <- explanations <- rep(list(""), nq)
type <- rep(list("num"),nq)

questions[[1]] = "What is the value of $b_2$ rounded to 3 digits?"
questions[[2]] = "What is the value of $b_3$ rounded to 3 digits?"
solutions[[1]] = b2
solutions[[2]] = b3
explanations[[1]] = paste("You have you substract the conditional mean of group 2 from the reference group 1. gives:",b2)
explanations[[2]] = paste("You have you substract the conditional mean of group 3 from the reference group 1",b3)
```


Question
========
You are given the following dataset on two variables `y` and `group`.

```{r showdata,echo=FALSE}
# kable(df,row.names = FALSE,align = "c")
df
```

some text with math

$y_i = b_0 + b_2 g_{2,i} + b_3 g_{3,i} + e_i$

```{r questionlist, echo = FALSE, results = "asis"}
answerlist(unlist(questions), markup = "markdown")
```

Solution
========

```{r sollist, echo = FALSE, results = "asis"}
answerlist(unlist(explanations), markup = "markdown")
```

Meta-information
================
extype: cloze
exsolution: `r paste(solutions,collapse = "|")`
exclozetype: `r paste(type, collapse = "|")`
exname: Dummy Manual computation
extol: 0.001






r dplyr exams






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 21 '18 at 14:47









Florian OswaldFlorian Oswald

2,16252027




2,16252027








  • 2





    Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

    – hrbrmstr
    Nov 21 '18 at 15:00













  • @hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

    – Florian Oswald
    Nov 22 '18 at 8:33














  • 2





    Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

    – hrbrmstr
    Nov 21 '18 at 15:00













  • @hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

    – Florian Oswald
    Nov 22 '18 at 8:33








2




2





Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

– hrbrmstr
Nov 21 '18 at 15:00







Totally not weird/strange. ?exams2html or go to github.com/cran/exams/blob/master/R/exams2html.R#L1-L5. There's an envir parameter. It's NULL by default so everything is going to run in a fresh environment when you call that function. That means it knows not of dplyr. Either put the library() call for dplyr in the Rmd or pass in the calling environment. I'd do the former. If you're worried about the package startup messages, suppress them. filter() just happens to be a stats function that the tidyverse brazenly overloaded.

– hrbrmstr
Nov 21 '18 at 15:00















@hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

– Florian Oswald
Nov 22 '18 at 8:33





@hrbrmstr not very helpful. 1) putting library(dplyr) in the Rmd file does not change a thing. 2) ?exams2html says envir: argument passed to xweave (which passes it to knit). now, package will be visible in any env: e=new.env();library(dplyr);exists("arrange",envir=e) 3) I ask a question on SO precisely s.t. I don't have to go and look at the source code. 4) This is a great package and I'm very grateful to the devs. Docs could be more complete, as always. not a critique, a fact. 5) end.

– Florian Oswald
Nov 22 '18 at 8:33












2 Answers
2






active

oldest

votes


















4














Thanks for raising this issue and to @hrbrmstr for explanation of one part of the problem. However, one part of the explanation is still missing:




  • Of course, the root of the problem is that both stats and dplyr export different filter() functions. And it can depend on various factors which function is found first.

  • In an interactive session it is sufficient to load the packages in the right order with stats being loaded automatically and dplyr subsequently. Hence this works:
    library("knitr")
    library("dplyr")
    knit("exam.Rmd")

  • It took me a moment to figure out what is different when you do:
    library("exams")
    library("dplyr")
    exams2html("exam.Rmd")

  • It turns out that in the latter code chunk knit() is called by exams2html() and hence the NAMESPACE of the exams package changes the search path because it fully imports the entire stats package. Therefore, stats::filter() is found before dplyr::filter() unless the code is evaluated in an environment where dplyr was loaded such as the .GlobalEnv. (For more details see the answer by @hrbrmstr)


As there is no pressing reason for the exams package to import the entire stats package, I have changed the NAMESPACE to import only the required functions selectively (which does not include the filter() function). Please install the development version from R-Forge:



install.packages("exams", repos = "http://R-Forge.R-project.org")


And then your .Rmd can be compiled without dplyr::... just by including library("dplyr") - either within the .Rmd or before calling exams2html(). Both should work now as expected.






share|improve this answer

































    1














    Using your exams.Rmd, this is the source pane where I'm about to hit cmd-enter:



    enter image description here



    (I added quiet=FALSE so I could see what was going on).



    Here's the console output after cmd-enter:



    enter image description here



    And here's the output:



    enter image description here



    If you read all the way through to the help on knit:





    • envir: Environment in which code chunks are to be evaluated, for example, parent.frame(), new.env(), or globalenv()).


    So parent.frame() or globalenv() is required vs what you did (you don't seem to fully understand environments). You get TRUE from your exists() call because by default inherits is TRUE in the exists function and that tells the function to "[search] the enclosing frames of the environment" (from the help on exists.



    And, you should care deeply about source code and triaging errors. You're using a programming language and open source software and you are right that the library(dplyr) didn't work inside the Rmd due to some terrible code choices in this "great" package and that you don't want pointed out since you don't want to look at source code.



    End, as I can do no more for you. I just hope others benefit from this.






    share|improve this answer





















    • 1





      thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

      – Florian Oswald
      Nov 22 '18 at 20:21











    Your Answer






    StackExchange.ifUsing("editor", function () {
    StackExchange.using("externalEditor", function () {
    StackExchange.using("snippets", function () {
    StackExchange.snippets.init();
    });
    });
    }, "code-snippets");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "1"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53414611%2fr-exams-package-weird-behaviour-with-dplyr%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    4














    Thanks for raising this issue and to @hrbrmstr for explanation of one part of the problem. However, one part of the explanation is still missing:




    • Of course, the root of the problem is that both stats and dplyr export different filter() functions. And it can depend on various factors which function is found first.

    • In an interactive session it is sufficient to load the packages in the right order with stats being loaded automatically and dplyr subsequently. Hence this works:
      library("knitr")
      library("dplyr")
      knit("exam.Rmd")

    • It took me a moment to figure out what is different when you do:
      library("exams")
      library("dplyr")
      exams2html("exam.Rmd")

    • It turns out that in the latter code chunk knit() is called by exams2html() and hence the NAMESPACE of the exams package changes the search path because it fully imports the entire stats package. Therefore, stats::filter() is found before dplyr::filter() unless the code is evaluated in an environment where dplyr was loaded such as the .GlobalEnv. (For more details see the answer by @hrbrmstr)


    As there is no pressing reason for the exams package to import the entire stats package, I have changed the NAMESPACE to import only the required functions selectively (which does not include the filter() function). Please install the development version from R-Forge:



    install.packages("exams", repos = "http://R-Forge.R-project.org")


    And then your .Rmd can be compiled without dplyr::... just by including library("dplyr") - either within the .Rmd or before calling exams2html(). Both should work now as expected.






    share|improve this answer






























      4














      Thanks for raising this issue and to @hrbrmstr for explanation of one part of the problem. However, one part of the explanation is still missing:




      • Of course, the root of the problem is that both stats and dplyr export different filter() functions. And it can depend on various factors which function is found first.

      • In an interactive session it is sufficient to load the packages in the right order with stats being loaded automatically and dplyr subsequently. Hence this works:
        library("knitr")
        library("dplyr")
        knit("exam.Rmd")

      • It took me a moment to figure out what is different when you do:
        library("exams")
        library("dplyr")
        exams2html("exam.Rmd")

      • It turns out that in the latter code chunk knit() is called by exams2html() and hence the NAMESPACE of the exams package changes the search path because it fully imports the entire stats package. Therefore, stats::filter() is found before dplyr::filter() unless the code is evaluated in an environment where dplyr was loaded such as the .GlobalEnv. (For more details see the answer by @hrbrmstr)


      As there is no pressing reason for the exams package to import the entire stats package, I have changed the NAMESPACE to import only the required functions selectively (which does not include the filter() function). Please install the development version from R-Forge:



      install.packages("exams", repos = "http://R-Forge.R-project.org")


      And then your .Rmd can be compiled without dplyr::... just by including library("dplyr") - either within the .Rmd or before calling exams2html(). Both should work now as expected.






      share|improve this answer




























        4












        4








        4







        Thanks for raising this issue and to @hrbrmstr for explanation of one part of the problem. However, one part of the explanation is still missing:




        • Of course, the root of the problem is that both stats and dplyr export different filter() functions. And it can depend on various factors which function is found first.

        • In an interactive session it is sufficient to load the packages in the right order with stats being loaded automatically and dplyr subsequently. Hence this works:
          library("knitr")
          library("dplyr")
          knit("exam.Rmd")

        • It took me a moment to figure out what is different when you do:
          library("exams")
          library("dplyr")
          exams2html("exam.Rmd")

        • It turns out that in the latter code chunk knit() is called by exams2html() and hence the NAMESPACE of the exams package changes the search path because it fully imports the entire stats package. Therefore, stats::filter() is found before dplyr::filter() unless the code is evaluated in an environment where dplyr was loaded such as the .GlobalEnv. (For more details see the answer by @hrbrmstr)


        As there is no pressing reason for the exams package to import the entire stats package, I have changed the NAMESPACE to import only the required functions selectively (which does not include the filter() function). Please install the development version from R-Forge:



        install.packages("exams", repos = "http://R-Forge.R-project.org")


        And then your .Rmd can be compiled without dplyr::... just by including library("dplyr") - either within the .Rmd or before calling exams2html(). Both should work now as expected.






        share|improve this answer















        Thanks for raising this issue and to @hrbrmstr for explanation of one part of the problem. However, one part of the explanation is still missing:




        • Of course, the root of the problem is that both stats and dplyr export different filter() functions. And it can depend on various factors which function is found first.

        • In an interactive session it is sufficient to load the packages in the right order with stats being loaded automatically and dplyr subsequently. Hence this works:
          library("knitr")
          library("dplyr")
          knit("exam.Rmd")

        • It took me a moment to figure out what is different when you do:
          library("exams")
          library("dplyr")
          exams2html("exam.Rmd")

        • It turns out that in the latter code chunk knit() is called by exams2html() and hence the NAMESPACE of the exams package changes the search path because it fully imports the entire stats package. Therefore, stats::filter() is found before dplyr::filter() unless the code is evaluated in an environment where dplyr was loaded such as the .GlobalEnv. (For more details see the answer by @hrbrmstr)


        As there is no pressing reason for the exams package to import the entire stats package, I have changed the NAMESPACE to import only the required functions selectively (which does not include the filter() function). Please install the development version from R-Forge:



        install.packages("exams", repos = "http://R-Forge.R-project.org")


        And then your .Rmd can be compiled without dplyr::... just by including library("dplyr") - either within the .Rmd or before calling exams2html(). Both should work now as expected.







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Jan 7 at 17:05

























        answered Nov 22 '18 at 20:19









        Achim ZeileisAchim Zeileis

        6,49612026




        6,49612026

























            1














            Using your exams.Rmd, this is the source pane where I'm about to hit cmd-enter:



            enter image description here



            (I added quiet=FALSE so I could see what was going on).



            Here's the console output after cmd-enter:



            enter image description here



            And here's the output:



            enter image description here



            If you read all the way through to the help on knit:





            • envir: Environment in which code chunks are to be evaluated, for example, parent.frame(), new.env(), or globalenv()).


            So parent.frame() or globalenv() is required vs what you did (you don't seem to fully understand environments). You get TRUE from your exists() call because by default inherits is TRUE in the exists function and that tells the function to "[search] the enclosing frames of the environment" (from the help on exists.



            And, you should care deeply about source code and triaging errors. You're using a programming language and open source software and you are right that the library(dplyr) didn't work inside the Rmd due to some terrible code choices in this "great" package and that you don't want pointed out since you don't want to look at source code.



            End, as I can do no more for you. I just hope others benefit from this.






            share|improve this answer





















            • 1





              thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

              – Florian Oswald
              Nov 22 '18 at 20:21
















            1














            Using your exams.Rmd, this is the source pane where I'm about to hit cmd-enter:



            enter image description here



            (I added quiet=FALSE so I could see what was going on).



            Here's the console output after cmd-enter:



            enter image description here



            And here's the output:



            enter image description here



            If you read all the way through to the help on knit:





            • envir: Environment in which code chunks are to be evaluated, for example, parent.frame(), new.env(), or globalenv()).


            So parent.frame() or globalenv() is required vs what you did (you don't seem to fully understand environments). You get TRUE from your exists() call because by default inherits is TRUE in the exists function and that tells the function to "[search] the enclosing frames of the environment" (from the help on exists.



            And, you should care deeply about source code and triaging errors. You're using a programming language and open source software and you are right that the library(dplyr) didn't work inside the Rmd due to some terrible code choices in this "great" package and that you don't want pointed out since you don't want to look at source code.



            End, as I can do no more for you. I just hope others benefit from this.






            share|improve this answer





















            • 1





              thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

              – Florian Oswald
              Nov 22 '18 at 20:21














            1












            1








            1







            Using your exams.Rmd, this is the source pane where I'm about to hit cmd-enter:



            enter image description here



            (I added quiet=FALSE so I could see what was going on).



            Here's the console output after cmd-enter:



            enter image description here



            And here's the output:



            enter image description here



            If you read all the way through to the help on knit:





            • envir: Environment in which code chunks are to be evaluated, for example, parent.frame(), new.env(), or globalenv()).


            So parent.frame() or globalenv() is required vs what you did (you don't seem to fully understand environments). You get TRUE from your exists() call because by default inherits is TRUE in the exists function and that tells the function to "[search] the enclosing frames of the environment" (from the help on exists.



            And, you should care deeply about source code and triaging errors. You're using a programming language and open source software and you are right that the library(dplyr) didn't work inside the Rmd due to some terrible code choices in this "great" package and that you don't want pointed out since you don't want to look at source code.



            End, as I can do no more for you. I just hope others benefit from this.






            share|improve this answer















            Using your exams.Rmd, this is the source pane where I'm about to hit cmd-enter:



            enter image description here



            (I added quiet=FALSE so I could see what was going on).



            Here's the console output after cmd-enter:



            enter image description here



            And here's the output:



            enter image description here



            If you read all the way through to the help on knit:





            • envir: Environment in which code chunks are to be evaluated, for example, parent.frame(), new.env(), or globalenv()).


            So parent.frame() or globalenv() is required vs what you did (you don't seem to fully understand environments). You get TRUE from your exists() call because by default inherits is TRUE in the exists function and that tells the function to "[search] the enclosing frames of the environment" (from the help on exists.



            And, you should care deeply about source code and triaging errors. You're using a programming language and open source software and you are right that the library(dplyr) didn't work inside the Rmd due to some terrible code choices in this "great" package and that you don't want pointed out since you don't want to look at source code.



            End, as I can do no more for you. I just hope others benefit from this.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Nov 22 '18 at 12:18

























            answered Nov 22 '18 at 11:58









            hrbrmstrhrbrmstr

            61.6k693153




            61.6k693153








            • 1





              thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

              – Florian Oswald
              Nov 22 '18 at 20:21














            • 1





              thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

              – Florian Oswald
              Nov 22 '18 at 20:21








            1




            1





            thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

            – Florian Oswald
            Nov 22 '18 at 20:21





            thanks, that's much more helpful! I have forgotten about the inherits argument, so that clarifies a lot. The fact that moving the library(dplyr) into the Rmd didn't make it work confused me a lot (you say it shouldn't be the case!), that's why I called it strange/weird. I found your initial comment a bit abrasive, for no good reason that I could see. That's why I responded like I did. The package resolves a lot of problems for me, hence it's great. I apologise if I interpreted your initial comment wrongly, and thanks for the complete answer.

            – Florian Oswald
            Nov 22 '18 at 20:21


















            draft saved

            draft discarded




















































            Thanks for contributing an answer to Stack Overflow!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53414611%2fr-exams-package-weird-behaviour-with-dplyr%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            How to change which sound is reproduced for terminal bell?

            Title Spacing in Bjornstrup Chapter, Removing Chapter Number From Contents

            Can I use Tabulator js library in my java Spring + Thymeleaf project?