R help - Jul 2018 - RStudio 1.1.453 - Windows 10 - How to see detailed results of every calculation step

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]]

Hello,

First of all welcome to R, I hope you enjoy it and that as you go along 
it will give less and less troubles.

Now, why would length(56) return 2? It's just one number, a vector of 
length 1.

Start by trying it at an R prompt and see the result.

Hope this helps,

Rui Barradas

?s 16:07 de 27-07-2018, ??????? ???? Ibrauheem Khat'taub
escreveu:
> 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]]
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Dear Ibrauheem

First try

length(56)

then try
rnorm()
using the value you got in stage 1

Michael

On 27/07/2018 16:07, ??????? ???? Ibrauheem Khat'taub
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]]
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
-- 
Michael
http://www.dewey.myzen.co.uk/home.html

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, "??????? ???? Ibrauheem
Khat'taub" <barhomopolis at 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]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
-- 
Sent from my phone. Please excuse my brevity.

You can readily do it yourself:

x <- 56
length(x) # hint: why do you expect length(56) to be 2?
rnorm(length(x))
x + rnorm(length(x))

For more complicated problems, the debugger is useful, but I almost always find
investigating the steps at the command line to be the most informative.

Sarah
On Jul 27, 2018, 9:38 AM -0600, ??????? ???? Ibrauheem Khat'taub
<barhomopolis at 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]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
	[[alternative HTML version deleted]]

Thanks a lot, Rui!



On Fri, 27 Jul 2018 at 12:02, Rui Barradas <ruipbarradas at sapo.pt>
wrote:
> Hello,
>
> First of all welcome to R, I hope you enjoy it and that as you go along
> it will give less and less troubles.
>
> Now, why would length(56) return 2? It's just one number, a vector of
> length 1.
>
> Start by trying it at an R prompt and see the result.
>
> Hope this helps,
>
> Rui Barradas
>
> ?s 16:07 de 27-07-2018, ??????? ???? Ibrauheem Khat'taub escreveu:
> > 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]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
	[[alternative HTML version deleted]]

Thanks a lot, Michael!



On Fri, 27 Jul 2018 at 12:12, Michael Dewey <lists at dewey.myzen.co.uk>
wrote:
> Dear Ibrauheem
>
> First try
>
> length(56)
>
> then try
> rnorm()
> using the value you got in stage 1
>
> Michael
>
> On 27/07/2018 16:07, ??????? ???? Ibrauheem Khat'taub 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]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
> --
> Michael
> http://www.dewey.myzen.co.uk/home.html
>
	[[alternative HTML version deleted]]

OMG, Jeff, this is so helpful of you!
Thanks a lot!


On Fri, 27 Jul 2018 at 12:32, Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
wrote:
> 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, "??????? ???? Ibrauheem
Khat'taub" <
> barhomopolis at 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]]
> >
> >______________________________________________
> >R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >https://stat.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide
> >http://www.R-project.org/posting-guide.html
> >and provide commented, minimal, self-contained, reproducible code.
>
> --
> Sent from my phone. Please excuse my brevity.
>
	[[alternative HTML version deleted]]

Thanks a lot, Sarah! Appreciate the help!


On Fri, 27 Jul 2018 at 12:55, Sarah Goslee <sarah.goslee at gmail.com>
wrote:
> You can readily do it yourself:
>
> x <- 56
> length(x) # hint: why do you expect length(56) to be 2?
> rnorm(length(x))
> x + rnorm(length(x))
>
> For more complicated problems, the debugger is useful, but I almost always
> find investigating the steps at the command line to be the most
informative.
>
> Sarah
> On Jul 27, 2018, 9:38 AM -0600, ??????? ???? Ibrauheem Khat'taub <
> barhomopolis at 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]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
	[[alternative HTML version deleted]]