Hi--
I too misread the question twice and i may have mistakenly posted non-text
answer earlier. Below is a step by step solution that works provided that
your real data frame has the same structure (alternative columns as in your
example). You could combine all the steps in 2 statements.
Best of luck
EK
a <- grep("_flag",colnames(mydf))
b <- mydf[,a]==0
c <- mydf[,a-1]
c[b] <- NA
mydf[,a-1] <- c
mydf
A A_flag B B_flag
1 8 10 5 12
2 NA 0 6 9
3 10 1 NA 0
4 NA 0 1 5
5 5 2 NA 0
On Wed, Nov 22, 2017 at 8:44 AM, Ek Esawi <esaw...@gmail.com> wrote:
> OPS,
>
> Sorry i did not read the post carfully. Mine will not work if you have
> zeros on columns A and B.. But you could modify it to work for specific
> columns i believe.
>
> EK
>
> On Wed, Nov 22, 2017 at 8:37 AM, Ek Esawi <esaw...@gmail.com> wrote:
>
>> Hi *Massimo,*
>>
>> *Try this.*
>>
>> *a <- mydf==0mydf[a] <- NAHTHEK*
>>
>> On Wed, Nov 22, 2017 at 5:34 AM, Massimo Bressan <
>> massimo.bres...@arpa.veneto.it> wrote:
>>
>>>
>>>
>>> Given this data frame (a simplified, essential reproducible example)
>>>
>>>
>>>
>>>
>>> A<-c(8,7,10,1,5)
>>>
>>> A_flag<-c(10,0,1,0,2)
>>>
>>> B<-c(5,6,2,1,0)
>>>
>>> B_flag<-c(12,9,0,5,0)
>>>
>>>
>>>
>>>
>>> mydf<-data.frame(A, A_flag, B, B_flag)
>>>
>>>
>>>
>>>
>>> # this is my initial df
>>>
>>> mydf
>>>
>>>
>>>
>>>
>>> I want to get to this final situation
>>>
>>>
>>>
>>>
>>> i<-which(mydf$A_flag==0)
>>>
>>> mydf$A[i]<-NA
>>>
>>>
>>>
>>>
>>> ii<-which(mydf$B_flag==0)
>>>
>>> mydf$B[ii]<-NA
>>>
>>>
>>>
>>>
>>> # this is my final df
>>>
>>> mydf
>>>
>>>
>>>
>>>
>>> By considering that I have to perform this task in a data frame with
>>> many columns I’m wondering if there is a compact and effective way to get
>>> the final result with just one ‘sweep’ of the dataframe?
>>>
>>>
>>>
>>>
>>> I was thinking to the function apply or lapply but I can not properly
>>> conceive how to…
>>>
>>>
>>>
>>>
>>> any hint for that?
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help@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/posti
>>> ng-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>>
>
[[alternative HTML version deleted]]
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