R help - Mar 2016 - Post: R-help : help with loops

Hello.

 

Im trying to post the following message in R-Help. 

 

I think I must send it via email to do so, so here it is:

 

Hello, 
I need help with some code. 
Basically, I have experiments results which I need to process. 

I have 2 dataframes with 3 columns 
Df1 <- data.frame (Date, Cellline, Data) 
Df2 <- data.frame (Date, Cellline, Control) 

I want for the entire column Df1-Data to be subtracted by the corresponding
Df2-Controls which Columns Date and Cellline coincide through some type of
loop. 
So the structure is: 

Df1$Data <- Df1$Data - Df2$Control [when (Df1$Celline == Df2$Celline &
Df1$Date == Df2$Date]) 

Each Control has several dozen Data values which are linked through Data and
Celline. Of course, the data.frames are of different dimensions. 

I've tried several approaches and failed miserably. 
Any suggestions? 

Thank you in advance for any.

 

Thanks.

 


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You made it. Next time set your email program to send plain text instead of HTML
format to avoid us receiving a corrupted version of what you sent. (This is a
plain text mailing list. )

You don't need looping, you need ?merge and ?ifelse.

Df1 <- merge( Df1, Df2, all.x = TRUE, by = c ( "Date",
"Cellline" ) )
# should now have a Control column in Df1 that is NA where there was no match
Df1$NewData  <- ifelse( is.na( Df1$Control ), Df1$Data, Df1$Data -
Df1$Control )

-- 
Sent from my phone. Please excuse my brevity.

On March 5, 2016 7:31:01 AM PST, Efres B <efresbr at hotmail.com>
wrote:
>Hello.
>
> 
>
>Im trying to post the following message in R-Help. 
>
> 
>
>I think I must send it via email to do so, so here it is:
>
> 
>
>Hello, 
>I need help with some code. 
>Basically, I have experiments results which I need to process. 
>
>I have 2 dataframes with 3 columns 
>Df1 <- data.frame (Date, Cellline, Data) 
>Df2 <- data.frame (Date, Cellline, Control) 
>
>I want for the entire column Df1-Data to be subtracted by the
>corresponding
>Df2-Controls which Columns Date and Cellline coincide through some type
>of
>loop. 
>So the structure is: 
>
>Df1$Data <- Df1$Data - Df2$Control [when (Df1$Celline == Df2$Celline
&
>Df1$Date == Df2$Date]) 
>
>Each Control has several dozen Data values which are linked through
>Data and
>Celline. Of course, the data.frames are of different dimensions. 
>
>I've tried several approaches and failed miserably. 
>Any suggestions? 
>
>Thank you in advance for any.
>
> 
>
>Thanks.
>
> 
>
>
>	[[alternative HTML version deleted]]
>
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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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