[R] save() and load()

[AbouEl-Makarim Aboueissa]

Hi Jeff: good morning

Thank you very much for your detailed explanation. Got it now.


With many thanks
Abou


On Mon, Sep 25, 2023, 9:46 PM Jeff Newmiller <jdnewmil using dcn.davis.ca.us>
wrote:

> You never created any object in R called irisdataTest. Objects in the
> global environment have names that are unrelated to the names of files on
> disk.
>
> The load function modifies an environment to create a variable named as it
> was named in the environment from which it was saved. Thus, you cannot
> simply load an object that was saved with one name into an object named
> something else. It is possible to create a new environment to put the
> loaded objects into, but I wouldn't recommend trying to explain how to do
> that to a beginner.  Rather, I would instead recommend using saveRDS and
> readRDS instead to save/load exactly one object at a time without storing
> the object name.
>
> saveRDS( mtcars, "my_mtcars.rds" )
> new_obj <- readRDS( "my_mtcars.rds" )
>
> I would also guide them to never save their environment when prompted by
> R... the .RData file this creates will remember mistakes made in previous
> sessions making troubleshooting very difficult later. Instead they should
> focus on making a top-to-bottom script that has all their analysis steps so
> they can start from scratch.
>
> On September 25, 2023 6:23:01 PM PDT, AbouEl-Makarim Aboueissa <
> abouelmakarim1962 using gmail.com> wrote:
> >Dear ALL:
> >
> >I am teaching statistical packages class this semester, in R programing I
> >am trying to explain the use of save() and load() with an example using
> the
> >iris data. It seems that the save() function works, BUT when I tried to
> >load the data back to R, it seems that there is a problem(s), I could not
> >figure out what went wrong.
> >
> >Any help would be highly appreciated.
> >
> >
> >I saved the iris data in my computer in the text format,
> "iris.with.head.txt
> >".
> >
> >Here are my R codes:
> >
> >> irisdata<-read.table("G:/iris.with.head.txt", header=T)
> >>
> >> head(irisdata)
> >  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
> >1          5.1         3.5          1.4         0.2  setosa
> >2          4.9         3.0          1.4         0.2  setosa
> >3          4.7         3.2          1.3         0.2  setosa
> >4          4.6         3.1          1.5         0.2  setosa
> >5          5.0         3.6          1.4         0.2  setosa
> >6          5.4         3.9          1.7         0.4  setosa
> >
> >
> >
> >*##### saving the data as an .rda*
> >
> >save(irisdata,file="G:/irisdataTest.rda")
> >
> >*##### load the data back to R*
> >
> >load(file="G:/irisdataTest.rda")
> >
> >
> >>head(irisdataTest)
> >Error in head(irisdataTest) : object 'irisdataTest' not found
> >
> >> irisdataTest
> >Error: object 'irisdataTest' not found
> >
> >
> >
> >with many thanks
> >abou
> >______________________
> >
> >
> >*AbouEl-Makarim Aboueissa, PhD*
> >
> >*Professor, Mathematics and Statistics*
> >*Graduate Coordinator*
> >
> >*Department of Mathematics and Statistics*
> >*University of Southern Maine*
> >
> >       [[alternative HTML version deleted]]
> >
> >______________________________________________
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> >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.
>

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