[R] How to visualise what code is processed within a for loop

[Luca Meyer]

Hi Bob,

Thank you for your suggestion. Actually d0 is a dataframe, does that change
something in the code you propose?

Kind regards,

Luca

2018-04-24 10:19 GMT+02:00 Bob O'Hara <rni.boh using gmail.com>:

> The loop never assigns anything to d0, only t. The first line makes t
> a character string "d0$V1" (or "d0$V2" etc.). The second line assigns
> either 0 or 1 to t.
>
> Looking at this, I don't think you've got into the R psychology (bad
> news if you want to use R, good news in many other ways). I assume d0
> is a list, so could you put the V's into a vector, and then just use
> this:
>
> d0$V <- sapply(d1[1:10,1], grepl, d0$X0)
>
> (I haven't checked it, but it looks,like it will do the trick. It
> returns a logical vector, so if you need integers, then use an
> as.numeric() around the right hand side. Or hope that R does type
> conversion for you when you need it)
>
> HTH
>
> Bob
>
> On 24 April 2018 at 09:30, Luca Meyer <lucam1968 using gmail.com> wrote:
> > Hi,
> >
> > I am trying to debug the following code:
> >
> > for (i in 1:10){
> >   t <- paste("d0$V",i,sep="")
> >   t <- ifelse(regexpr(d1[i,1],d0$X0)>0,1,0)
> > }
> >
> > and I would like to see what code is actually processing R, how can I do
> > that?
> >
> > More to the point, I am trying to update my variables d0$V1 to d0$V10
> > according to the presence or absence of some text (contained in the file
> > d1) within the d0$X0 variable.
> >
> > The code seem to run ok, if I add print(table(t)) within the loop I can
> see
> > that the ifelse procedure is working and to some cases within the d0$V1
> to
> > d0$V10 variable range a 1 is assigned. But when checking my d0$V1 to
> d0$V10
> > after the for loop they are all still equal to zero...
> >
> > Thanks,
> >
> > Luca
> >
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> >
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>
> --
> Bob O'Hara
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