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

[PIKAL Petr]

Hi

Maybe I am missing something but in package "zoo" is function "na.locf", which fills empty cells with previous value.

So when you read your file

dat<-read.table("....", na="")

you can use

library(zoo)
sapply(dat, na.locf)

the only problem is that it changes factors to numeric representation. It is solved here

https://stackoverflow.com/questions/22771260/na-locf-converts-data-from-numeric-to-character

Cheers
Petr

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Christophe
> Elek
> Sent: Sunday, June 25, 2017 5:26 PM
> To: Boris Steipe <boris.steipe at utoronto.ca>
> Cc: r-help at r-project.org
> Subject: Re: [R] Fill in empty cell in data.frame from previous value
>
> Excellent Boris, thx – this helps
>
> From: Boris Steipe
> Sent: June 25, 2017 11:23 AM
> To: Christophe Elek
> Cc: r-help at r-project.org
> Subject: Re: [R] Fill in empty cell in data.frame from previous value
>
> Run it through a loop. I assume the cell contents is NA (Not Available). Test for
> it with is.na(). Whenever that returns TRUE, replace the NA value with the
> value from the previous row.
>
> Cheers,
> B.
>
>
>
> > On Jun 24, 2017, at 1:49 PM, 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]]
> >
> > ______________________________________________
> > 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]]
>
> ______________________________________________
> 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.

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