[R] Odp: conditional data replace (recode, change or whatsoever)

[Petr PIKAL]

Hi
> 
> Hello,
> I have a big data.frame, a piece of it as follows.
> 
>     a           b              c       d
> 1   58009   2010-11-02   0       NA
> 2   114761   NA              1       2008-11-05
> 3   184440   NA              1       2009-12-08
> 4   189372   NA              0       NA
> 5   105286   NA              0       NA
> 6   186717   NA              0       NA
> 7   189106   NA              0       NA
> 8   127306   NA              0       NA
> 9   157342   2011-04-25   0       NA
> 
> I want to replace b[NA] values with "20011-07-28" where c==0. I use 
rstudio
> and i'm a novice.

I believe there are better solutions but I would use two steps

select rows where c==0 (see also FAQ 7.31)
sel<-which(big.data.frame$c==0)

change NA values in b column based on sel
big.data.frame$b[sel][is.na(big.data.frame$b[sel])]<-"20011-07-28"

Beware of data types AFAIK R can not accept "20011-07-28" as a date.

Regards
Petr

> 
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