Folks:
1. Ankur needs to read "An Introduction to R" or other R tutorial (on the
web, say), as it appears that he has not made much of an effort to learn
how R works. In particular, R is not a data base and does not (normally, at
user level) use pointers/references. So no automatic updating.
2. In Rui's code below, the result of course needs to be assigned:
dat <- fun(dat)
Cheers,
Bert
On Sat, Sep 7, 2013 at 4:27 AM, Rui Barradas <ruipbarra...@sapo.pt> wrote:
> Hello,
>
> What you can do is to write a function to do the change. When you want to
> change a value in column Value, it will update the value in column New.
> Something like this:
>
>
> fun <- function(data, row, newval){
> data$Value[row] <- newval
> data$New <- c(NA, diff(data$Value))
> data
> }
>
> fun(dat, 2, 101.5)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 07-09-2013 12:19, Ankur Seth escreveu:
>
>> Is there a way in which I can setup a model like that?
>>
>> Regards,
>> Ankur Seth
>>
>>
>> On Sat, Sep 7, 2013 at 4:49 PM, Rui Barradas <ruipbarra...@sapo.pt>
>> wrote:
>>
>> Hello,
>>>
>>> It will not change the value automatically, you will have to rerun the
>>> code.
>>>
>>> Rui Barradas
>>>
>>> Em 07-09-2013 11:52, Ankur Seth escreveu:
>>>
>>> Thanks Rui, but this does not change the value in the new column
>>>> automatically if I change the value in the data column. Any ideas?
>>>>
>>>> Regards,
>>>> Ankur Seth
>>>>
>>>>
>>>> On Sat, Sep 7, 2013 at 2:11 PM, Rui Barradas <ruipbarra...@sapo.pt>
>>>> wrote:
>>>>
>>>> Hello,
>>>>
>>>>>
>>>>> Try the following.
>>>>>
>>>>> dat <- read.table(text = "
>>>>>
>>>>> Date Value
>>>>> 08/01/2013 100
>>>>> 08/02/2013 100.5
>>>>> 08/03/2013 102
>>>>> ", header = TRUE)
>>>>>
>>>>>
>>>>> dat$New <- c(NA, diff(dat$Value))
>>>>> dat
>>>>>
>>>>>
>>>>> Hope this helps,
>>>>>
>>>>> Rui Barradas
>>>>>
>>>>> Em 07-09-2013 06:06, Ankur Seth escreveu:
>>>>>
>>>>> Hello All,
>>>>>
>>>>>>
>>>>>> I am trying to build a model in R. I am facing the following
>>>>>> problem...
>>>>>>
>>>>>> My Data Frame contains the following data...
>>>>>>
>>>>>> Date Value
>>>>>> 08/01/2013 100
>>>>>> 08/02/2013 100.5
>>>>>> 08/03/2013 102
>>>>>> ....
>>>>>>
>>>>>> Now I want to add a column to this data frame where New Column Value =
>>>>>> Difference of two subsequent observations. For Eg. on 08/02/2013 the
>>>>>> new
>>>>>> value = 100.5 - 100=0.5
>>>>>>
>>>>>> I want to do this dynamically such that if I change the value in Value
>>>>>> column the new column should recalculate automatically.
>>>>>>
>>>>>> Is there a way to do this in R?
>>>>>>
>>>>>> Regards,
>>>>>> Ankur Seth
>>>>>>
>>>>>> [[alternative HTML version deleted]]
>>>>>>
>>>>>> ______________________________******________________
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>>>>>> https://stat.ethz.ch/mailman/******listinfo/r-help<https://stat.ethz.ch/mailman/****listinfo/r-help>
>>>>>> <https://**stat.ethz.ch/mailman/****listinfo/r-help<https://stat.ethz.ch/mailman/**listinfo/r-help>
>>>>>> >
>>>>>> <https://stat.**ethz.ch/**mailman/listinfo/r-**help<http://ethz.ch/mailman/listinfo/r-**help>
>>>>>> <http**s://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>>>>>> >
>>>>>>
>>>>>>>
>>>>>>> PLEASE do read the posting guide http://www.R-project.org/**
>>>>>> posting-guide.html
>>>>>> <http://www.R-project.org/****posting-guide.html<http://www.R-project.org/**posting-guide.html>
>>>>>> <http://www.**R-project.org/posting-guide.**html<http://www.R-project.org/posting-guide.html>
>>>>>> >
>>>>>>
>>>>>>>
>>>>>>>
>>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>
>>>>
>>
>>
> ______________________________**________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/**
> posting-guide.html <http://www.R-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
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