[R] Fw: Using if, else statements

[Gabriela Cendoya]

Sorry in the previos replay I forgot monday' scale
so weight should be:
weight <- c(0.91,1,1,1,1,1.21,1.22)
names(weight) <- c("mon","tue","wed","thu","fri","sat","sun")


----- Original Message ----- 
From: "Gabriela Cendoya" <gcendoya at balcarce.inta.gov.ar>
To: "Robin Williams" <>
Cc: <>
Sent: Wednesday, July 23, 2008 4:14 PM
Subject: Re: [R] Using if, else statements


> Hi Robin:
>                I think you can avoid the loops doing this:
>
> my.df<-data.frame(d.o.w=sample(c("mon","sat","sun"), 20, replace=T),
>       admissions=rnorm(20))
> weight <- c(1,1,1,1,1,1.21,1.22)
> names(weight) <- c("mon","tue","wed","thu","fri","sat","sun")
> my.df$NewAdm <- my.df$admissions * weight[as.character(my.df$d.o.w)]
>
> my.df
>
> Gabriela
>
>
>
> ----- Original Message ----- 
> From: "Robin Williams" <robster3 at hotmail.com>
> To: <r-help at r-project.org>
> Sent: Wednesday, July 23, 2008 12:44 PM
> Subject: [R] Using if, else statements
>
>
>> Hi all,
>>
>> Again I have searched the net and so on, without finding an answer to 
>> this
>> surely simple problem. A short bit of code would be appreciated.
>>
>>  I have a object named `data' with the following column headings.
>>
>> Date, maxitemp, minitemp, admissions, d.o.w.
>>
>> Where d.o.w. is day of the week, written "Sun" "Mon" etc.
>>
>>  I just need to scale the Monday admissions by 0.91, the Saturday
>> admissions by 1.21 and the Sunday admissions by 1.22. So basically what I
>> want is:
>>
>> If d.o.w. == "Sat"
>>
>> Multiply Sat admissions by 1.21.
>>
>> (Now do I need an else statement here, or can I just do another)
>>
>> If d.o.w. == "Sun"
>>
>> Multiply "Sun" admissions by 1.22
>>
>> (and finally)
>>
>> If d.o.w. == "Mon"
>>
>> Multiply Monday admissions by 0.91.
>>
>> Else do nothing.
>>
>>  I assume in my code I need to specify that I am using the data.frame
>> `data', so do I need to write things like
>>
>> If(data[d.o.w.]=="Mon")
>>
>>  I would then like to round the new admissions to integers (I assume I 
>> just
>> use round(data$admissions)), and output the new data to another csv file.
>>
>>  I could of course do this in excel but I will need to extend this type 
>> of
>> idea in the future so I would like to master it in R.
>>
>> Many thanks for any help/code.
>>
>> Robin Williams.
>>
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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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