[R] RStudio 1.1.453 - Windows 10 - How to see detailed results of every calculation step
Jeff Newmiller
jdnewm|| @end|ng |rom dcn@d@v|@@c@@u@
Fri Jul 27 18:32:37 CEST 2018
Debugging in R applies one statement at a time. If you want to debug within a statement you can "step into" the function calls within the statement or you can execute the function calls separately and inspect the result. Your function consists of one statement so the debugger only has one place to stop. However, once stopped, you can execute
length(x)
and get a result 1 instead of 2 as you are erroneously expecting.
The length function in R is NOT the equivalent of the LEN function in Excel... it tells you how many elements are in the vector, not the number of digits in a numeric or the number of characters in a string.
Does
AddLengthNoise( rep(56, 2) ) behave as desired?
On July 27, 2018 8:07:41 AM PDT, "إبراهيم خطاب Ibrauheem Khat'taub" <barhomopolis using gmail.com> wrote:
>Hi everyone,
>
>I am taking my first R course. This was my first example.
>
>When I executed:
>
>AddLengthNoise <- function(x) {x + rnorm(length(x))}
>
>using 56 as the value of x, I expected the result to be two values,
>something like:
>
>[1] 56.17491697 56.02935105
>
>because I expected rnorm to return two values and then 56 to be added
>to
>each of them. Instead, I got one value, something like:
>
>[1] 56.17491697
>
>So I wondered how this happened and wanted to see what happens behind
>the
>scene. Coming from the Excel paradigm, I wondered, "Is there something
>like
>'show calculation steps' in R?" So I Googled it, and got nothing
>related
>but this
><https://support.rstudio.com/hc/en-us/articles/205612627-Debugging-with-RStudio>.
>So, I tried breaking my code into separate lines and toggling
>breakpoints
>at all lines, as follows:
>
>6| AddLengthNoise <- function(x) {
>
> - 7| x +
> - 8| rnorm(
> - 9| length(
> - 10| x)
> - 11| )
> - 12| }
>
>(Where the bullet points above represent the red debugging checkpoints)
>
>Then I tried again:
>
>AddLengthNoise(56)
>
>and as I executed step by step, I could not see what I expected. I
>couldn't
>see each step's result, and I did not understand what I saw neither in
>the
>console nor in the "Traceback" window that appeared.
>
>My 2 questions:
>
> 1. Did I do something wrong?
>2. Is there a way to see, like in Excel's "Show calculation steps", the
> result of each step alone (i.e. length(56)=2 ==> rnorm(2)={0.17491697;
> 0.02935105} ==> 56 + {0.17491697; 0.02935105}= ... and so on)?
>
> [[alternative HTML version deleted]]
>
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--
Sent from my phone. Please excuse my brevity.
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