[R] Fill in empty cell in data.frame from previous value

[Jim Lemon]

That's the kind of help that we like to provide. And for extra marks, you
can write a small function that will deal with consecutive NA values.

Jim

On Mon, Jun 26, 2017 at 1:25 AM, Christophe Elek <christophe.elek at gmail.com>
wrote:

> Perfect Jim, that Is exactly what I needed – let me check that ...
>
> Cheers
>
>
>
> *From: *Jim Lemon <drjimlemon at gmail.com>
> *Sent: *June 25, 2017 3:11 AM
> *To: *Christophe Elek <christophe.elek at gmail.com>
> *Cc: *r-help at r-project.org
> *Subject: *Re: [R] Fill in empty cell in data.frame from previous value
>
>
>
> Hi Chris,
>
> You may know about the *apply family of functions. These slice various
>
> data structures and "apply" a specified function to each slice,
>
> usually returning a list of return values. As far as I am aware, you
>
> can't access adjacent rows unless you reformat the data structure.
>
>
>
> There is a way to do this particular job. It requires the sequence
>
> operator (:), the ifelse function and indexing. What you do is to
>
> create a sequence of all the values in the element "names", then
>
> subtract 1 for all the NA (or any other specified value) values and
>
> use the resulting vector to index the original element "names". It
>
> won't work if the first value is NA, nor will it work for more than
>
> one NA in a row. I realize that this is pretty obscure, but you said
>
> that you didn't just want the solution. It's a one-liner.
>
>
>
> Jim
>
>
>
> On Sun, Jun 25, 2017 at 3:49 AM, Christophe Elek
>
> <christophe.elek at gmail.com> wrote:
>
> > Hello Total newbie here... I hope I read the guide properly
>
> >
>
> > I have the following data.frame (I read it from a CSV file I cannot
> change)
>
> >
>
> >   names val
>
> > 1 Mandy   1
>
> > 2         2
>
> > 3 John    2
>
> > 4         2
>
> >
>
> > I want to read the row number 2, but I want the first column to be
> “Mandy” and not null
>
> >
>
> > print (frame[2,])
>
> > 2 Mandy   2
>
> >
>
> > I can manipulate the data.frame once loaded
>
> > How can I fill all cell in column “names” with the previous value ?
>
> > Or is there a function that will get me the row and fill the “names”
> column ?
>
> >
>
> > NOTA BENE: I do not want the answer, I want to find it myself but I need
> guidance
>
> > If there is a function, tell me the library and I will search
>
> > If this is an algorithm, tell me generally how you would do and let me
> scratch my head first 😊
>
> >
>
> > Thanks Chris
>
> >
>
> >
>
> >         [[alternative HTML version deleted]]
>
> >
>
> > ______________________________________________
>
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>
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>
> > PLEASE do read the posting guide http://www.R-project.org/
> posting-guide.html
>
> > and provide commented, minimal, self-contained, reproducible code.
>
>
>

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