R help - Mar 2010 - How to use the paste function to create an already used variable

Hi there,

I have the following problem

Four data frames exist:

data1
data2
data3
data4

Now I want to write a loop and temporarily store the data1, data2, 
data3, data4 in a variable called data.
I tried the following...

for (i in 1:4) {
Data <- paste("data",i,sep="")
...
..
}


but it doesn't function. I think the problem is the definition of the 
mode of the pasted variable.

Could anyone help me?
Thanks

Greetings
J?rgen

Try:

for (i in 1:4) {
Data <- eval(parse(text =  paste("data",i,sep="")))
...
..
}


(and if there are other solutions - I would love to know)



----------------Contact
Details:-------------------------------------------------------
Contact me: Tal.Galili@gmail.com |  972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)
----------------------------------------------------------------------------------------------




2010/3/24 "Biedermann, Jürgen" <juergen.biedermann@charite.de>
> Hi there,
>
> I have the following problem
>
> Four data frames exist:
>
> data1
> data2
> data3
> data4
>
> Now I want to write a loop and temporarily store the data1, data2, data3,
> data4 in a variable called data.
> I tried the following...
>
> for (i in 1:4) {
> Data <- paste("data",i,sep="")
> ...
> ..
> }
>
>
> but it doesn't function. I think the problem is the definition of the
mode
> of the pasted variable.
>
> Could anyone help me?
> Thanks
>
> Greetings
> Jürgen
>
> ______________________________________________
> R-help@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.
>
	[[alternative HTML version deleted]]

Try this:

Data <- lapply(ls(pattern = 'data[0-9]'), get)

Data[[1]] is data1
Data[[2]] is data2
....
etc.

2010/3/24 "Biedermann, J?rgen" <juergen.biedermann at
charite.de>:
> Hi there,
>
> I have the following problem
>
> Four data frames exist:
>
> data1
> data2
> data3
> data4
>
> Now I want to write a loop and temporarily store the data1, data2, data3,
> data4 in a variable called data.
> I tried the following...
>
> for (i in 1:4) {
> Data <- paste("data",i,sep="")
> ...
> ..
> }
>
>
> but it doesn't function. I think the problem is the definition of the
mode
> of the pasted variable.
>
> Could anyone help me?
> Thanks
>
> Greetings
> J?rgen
>
> ______________________________________________
> 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.
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O

Perfekt!

So, the code below does, what I want it does.

for (m in 1:AnzRat) {
    Daten_akt <-
eval(parse(text=paste("Daten",m,"_akt",sep="")))
    ...
    ...
   
assign(paste("Daten",m,"_akt",sep=""),Daten_akt)
}


Patrick Burns schrieb:
> I think you are looking for 'assign'.
>
> On 25/03/2010 09:40, "Biedermann, Jürgen" wrote:
>   
>> Thank you very much for the solutions! :-)
>>
>> It's my fault, but I forgot to mention that at the end of the loop,
I
>> would like to give
>>
>> "Data" back to data1, data2, data3, data4
>>
>> The eval formula only seems to work in one direction (it's the same
with
>> the get function)
>>
>> for (i in 1:4) {
>>          Data[[i]]<- eval(parse(text = 
paste("data",i,sep="")))
>> 	...
>> 	...
>> 	
>> 	eval(parse(text =  paste("data",i,sep="")))<-
Data[[i]] # -->  I get an error message here
>>
>>
>> }
>>
>> I know that generally it's much better to stick to lists in this
kind of kontext,
>> but I don't wanna change the whole structure of the rest of my
code.
>>
>> Thanks
>>
>> Greetings
>> Jürgen
>>
>>
>>
>>
>>
>>
>> David Winsemius schrieb:
>>     
>>> On Mar 24, 2010, at 9:25 AM, Tal Galili wrote:
>>>
>>>
>>>       
>>>> Try:
>>>>
>>>> for (i in 1:4) {
>>>> Data<- eval(parse(text = 
paste("data",i,sep="")))
>>>> ...
>>>> ..
>>>> }
>>>>
>>>>
>>>> (and if there are other solutions - I would love to know)
>>>>
>>>>         
>>> Well, it's not actually a solution since the first three
fetched
>>> values would have been overwritten.
>>>
>>> Instead:
>>>
>>>    Data<- list()
>>>    for (i in 1:4) {
>>>          Data[[i]]<- eval(parse(text = 
paste("data",i,sep=""))) }
>>>
>>>       
>>>> ----------------Contact
>>>> Details:-------------------------------------------------------
>>>> Contact me: Tal.Galili@gmail.com |  972-52-7275845
>>>> Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il
>>>> (Hebrew) |
>>>> www.r-statistics.com (English)
>>>>
----------------------------------------------------------------------------------------------
>>>>
>>>>
>>>>
>>>>
>>>> 2010/3/24 "Biedermann,
Jürgen"<juergen.biedermann@charite.de>
>>>>
>>>>
>>>>         
>>>>> Hi there,
>>>>>
>>>>> I have the following problem
>>>>>
>>>>> Four data frames exist:
>>>>>
>>>>> data1
>>>>> data2
>>>>> data3
>>>>> data4
>>>>>
>>>>> Now I want to write a loop and temporarily store the data1,
data2,
>>>>> data3,
>>>>> data4 in a variable called data.
>>>>> I tried the following...
>>>>>
>>>>> for (i in 1:4) {
>>>>> Data<- paste("data",i,sep="")
>>>>> ...
>>>>> ..
>>>>> }
>>>>>
>>>>>
>>>>> but it doesn't function. I think the problem is the
definition of
>>>>> the mode
>>>>> of the pasted variable.
>>>>>
>>>>> Could anyone help me?
>>>>> Thanks
>>>>>
>>>>> Greetings
>>>>> Jürgen
>>>>>
>>>>> ______________________________________________
>>>>> R-help@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.
>>>>>
>>>>>
>>>>>           
>>>> 	[[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> R-help@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.
>>>>
>>>>         
>>> David Winsemius, MD
>>> West Hartford, CT
>>>
>>>
>>>       
>> 	[[alternative HTML version deleted]]
>>
>>
>>
>>
>> ______________________________________________
>> R-help@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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