Fill in empty cell in data.frame from previous value

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


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