Apologies to list: Should have "replied to all".
--
DW
Begin forwarded message:
> From: David Winsemius <dwinsem...@comcast.net>
> Date: August 1, 2009 3:02:58 PM EDT
> To: Meenu Sahi <meenus...@gmail.com>
> Subject: Re: [R] Add columns in a dataframe and fill them from
> another table according to a criteria
>
>
> On Aug 1, 2009, at 1:43 PM, Meenu Sahi wrote:
>
>> Dear R users
>> My apologizes for not writing in the correct format due to my
>> ignorance. In the future I will write more clearly. I hope to
>> contribute to the R community in the process of picking up the
>> language professionally.
>> I have now written the R code which is attached in a notepad file.
>> I've simplified my problem in an example of, table pstate which
>> contains the probabilities of getting certain changes in the four
>> different states and a dataframe mydata4 which contains all the
>> changes connected to the four different states. I would like to add
>> the probabilities into mydata4 after matching for the change and
>> the state.
>> Everything before ##### output can be copy pasted in the R window.
>> The desired output is written after ###### OUTPUT
>> Must I write an if else or can I do it in an easier way?
>> Your help is greatly appreciated ! Many thanks for your patience.
>
> You need to figure out how to send mail to the list with plain text.
> But I suspect you did successfully get the attchment through to the
> audience.
>
> I did not like the ordering of the PStates in your new target
> dataframe so I changed it to fit my(and your) purposes.
>
> > Change<-c("b","a","b","c","d","a")
> > State<-c("State1","State4","State2","State3","State1","State3")
> >
> > mydata4<-data.frame(Change,State)
> > mydata4<-data.frame(mydata4,
> + PState1=NA,
> + PState2=NA,
> + PState3=NA,
> + PState4=NA
> + )
> > mydata4
> Change State PState1 PState2 PState3 PState4
> 1 b State1 NA NA NA NA
> 2 a State4 NA NA NA NA
> 3 b State2 NA NA NA NA
> 4 c State3 NA NA NA NA
> 5 d State1 NA NA NA NA
> 6 a State3 NA NA NA NA
>
> Note that str(pstate shows that State is a factor which becomes
> important.
>
> This now effects the desired transformation:
>
> for (i in 1:length(mydata4) )
> { mydata4[i, as.numeric( mydata4[i, "State"])+2 ] <-
> #assign to the i-th row, State + 2 column in
> mydata4 ...
> pstate[ mydata4[i, "Change"], as.numeric( mydata4[i,
> "State"])+1 ] }
> #... the value of i-th row, State+1 column of pstate
>
> > mydata4
> Change State PState1 PState2 PState3 PState4
> 1 b State1 Pb1 <NA> <NA> <NA>
> 2 a State4 <NA> <NA> <NA> Pa4
> 3 b State2 <NA> Pb2 <NA> <NA>
> 4 c State3 <NA> <NA> Pc3 <NA>
> 5 d State1 Pd1 <NA> <NA> <NA>
> 6 a State3 <NA> <NA> Pa3 <NA>
>
> The main non-obvious "trick" is the as.numeric( mydata4[i,
> "State"]) bit. as.numeric() when applied to a factor results in a
> numeric offset derived from the factor coding rather than using the
> level names. I suppose I could have left the PState<n>'s in the
> original order but then I would have been subtracting them from 7 to
> get the proper column number. Seemed even less understandable
>
>>
>> Regards
>> Meenu
>>
>> On Sat, Aug 1, 2009 at 9:43 PM, David Winsemius <dwinsem...@comcast.net
>> > wrote:
>>
>> On Aug 1, 2009, at 9:52 AM, Meenu Sahi wrote:
>>
>> Deare R users
>>
>> I am new to R.
>> What I want to do is explained below;-
>> I have table called States.Prob which is given below:-
>> This table gives the probabilities of the changes in the swap curve
>> depending on the state of the swap curve. I want to put these
>> probabilities
>> in my dataframe mydata(given after the prob table).
>> Prob of States
>> Changes State1 State2 State3 State4
>> a Pa1 Pa2 Pa3 Pa4
>> b Pb1 Pb2 Pb3 Pb4
>> c Pc1 Pc2 Pc3 Pc4
>> d Pd1 Pd2 Pd3 Pd4
>>
>> and I have a dataframe(with 93 rows) called mydata part of which(6
>> rows) is
>> given below where I want to fill in the last four columns with
>> probabilities
>> taken from States.Prob according to the change and state in mydata4:-
>> Change State PState1 PState2 PState3 PState4
>> 1 b State1 Pb1
>> 2 a State4 Pa4
>> 3 b State2 Pb2
>> 4 c State3 Pc3
>> 5 d State1 Pd1
>> 6 a State3 Pa3
>>
>> What I want to do is highlighted in Red.
>> How can I do this easily?
>>
>> You may have seen it in red, but we don't, ....and I, at least,
>> cannot figure out what you intend. (Per the Posting Guide, which
>> you have obviously not yet read, you need to compose your question
>> in plain old monochromatic text and change your mail client so it
>> posts in plain text.)
>>
>> If looking at the help pages for stack() and reshape() does not
>> offer useful information and worked examples that meet your needs
>> then:
>>
>> An approach that would make you more populat in these parts would
>> be to make a simpler example, composed in syntactically correct R,
>> that is complete in itself, and can pasted into an R session.
>> Indicate what you intend as output from this simpler input.
>>
>> Perhaps....
>>
>> > pstate <- read.table(textConnection("Changes State1 State2
>> State3 State4
>>
>> + a Pa1 Pa2 Pa3 Pa4
>> + b Pb1 Pb2 Pb3 Pb4
>> + c Pc1 Pc2 Pc3 Pc4
>> + d Pd1 Pd2 Pd3 Pd4"), header=TRUE,
>> as.is=TRUE)
>>
>> ?stack
>>
>> > data.frame(Change=pstate[,1],
>> prstate =stack(pstate[2:5])$values,
>> state=stack(pstate[2:5])$ind )
>>
>> #first column is only 4 elements long, but will get recycled
>> # second retreives the probabilities and may need to have
>> as.numeric( ) wrapped around it if they really are numeric.
>> # third returns what started out as column names.
>>
>> Change prstate state
>> 1 a Pa1 State1
>> 2 b Pb1 State1
>> 3 c Pc1 State1
>> 4 d Pd1 State1
>> 5 a Pa2 State2
>> 6 b Pb2 State2
>> 7 c Pc2 State2
>> 8 d Pd2 State2
>> 9 a Pa3 State3
>> 10 b Pb3 State3
>> 11 c Pc3 State3
>> 12 d Pd3 State3
>> 13 a Pa4 State4
>> 14 b Pb4 State4
>> 15 c Pc4 State4
>> 16 d Pd4 State4
>>
>>
>> Many thanks for your time.
>>
>> kind regards
>> Meenu
>> P.S. Thanks for your reply John. I've tried to put only the
>> relevant columns
>> of the dataframe. Hope its more clear now.
>>
>> \\\\\\\\\\\\\\\\\\//////////////////
>> [[alternative HTML version deleted]]
>>
>> ^^^^^^^^^^^^^^Note: ^^^^^^^^^^^^^^^^^^^^^^
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>>
>> <Input and Output.txt>
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
[[alternative HTML version deleted]]
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