Dear Lily,

Harold is telling you to type "?round" at the R command prompt to pull
up the "round" help page.

>?round
>help("round")

AFAIK, the above two commands are equivalent, in general.

Best, Bill.

W. Michels, Ph.D.



On Tue, May 9, 2017 at 8:11 AM, Doran, Harold <hdo...@air.org> wrote:
> ?round
>
>
> From: lily li [mailto:chocol...@gmail.com]
> Sent: Tuesday, May 09, 2017 11:10 AM
> To: Charles Determan <cdeterma...@gmail.com>
> Cc: Doran, Harold <hdo...@air.org>; R mailing list <r-help@r-project.org>
> Subject: Re: [R] About calculating average values from several matrices
>
> Thanks very much, it works. But how to round the values to have only 1 
> decimal digit or 2 decimal digits? I think by dividing, the values are double 
> type now. Thanks again.
>
>
> On Tue, May 9, 2017 at 9:04 AM, Charles Determan 
> <cdeterma...@gmail.com<mailto:cdeterma...@gmail.com>> wrote:
> If you want the mean of each element across you list of matrices the 
> following should provide what you are looking for where Reduce sums all your 
> matrix elements across matrices and the simply divided my the number of 
> matrices for the element-wise mean.
>
> Reduce(`+`, mylist)/length(mylist)
> Regards,
> Charles
>
> On Tue, May 9, 2017 at 9:52 AM, lily li 
> <chocol...@gmail.com<mailto:chocol...@gmail.com>> wrote:
> I meant for each cell, it takes the average from other dataframes at the
> same cell. I don't know how to deal with row names and col names though, so
> it has the error message.
>
> On Tue, May 9, 2017 at 8:50 AM, Doran, Harold 
> <hdo...@air.org<mailto:hdo...@air.org>> wrote:
>
>> It’s not clear to me what your actual structure is. Can you provide
>> str(object)? Assuming it is a list, and you want the mean over all cells or
>> columns, you might want like this:
>>
>>
>>
>> myData <- vector("list", 3)
>>
>>
>>
>> for(i in 1:3){
>>
>>                 myData[[i]] <- matrix(rnorm(100), 10, 10)
>>
>>                 }
>>
>>
>>
>> ### mean over all cells
>>
>> sapply(myData, function(x) mean(x))
>>
>>
>>
>> ### mean over all columns
>>
>> sapply(myData, function(x) colMeans(x))
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> *From:* lily li [mailto:chocol...@gmail.com<mailto:chocol...@gmail.com>]
>> *Sent:* Tuesday, May 09, 2017 10:44 AM
>> *To:* Doran, Harold <hdo...@air.org<mailto:hdo...@air.org>>
>> *Cc:* R mailing list <r-help@r-project.org<mailto:r-help@r-project.org>>
>> *Subject:* Re: [R] About calculating average values from several matrices
>
>>
>>
>>
>> I'm trying to get a new dataframe or whatever to call, which has the same
>> structure with each file as listed above. For each cell in the new
>> dataframe or the new file, it is the average value from former dataframes
>> at the same location. Thanks.
>>
>>
>>
>> On Tue, May 9, 2017 at 8:41 AM, Doran, Harold 
>> <hdo...@air.org<mailto:hdo...@air.org>> wrote:
>>
>> Are you trying to take the mean over all cells, or over rows/columns
>> within each dataframe. Also, are these different dataframes stored within a
>> list or are they standalone?
>>
>>
>>
>>
>> -----Original Message-----
>> From: R-help 
>> [mailto:r-help-boun...@r-project.org<mailto:r-help-boun...@r-project.org>] 
>> On Behalf Of lily li
>> Sent: Tuesday, May 09, 2017 10:39 AM
>> To: R mailing list <r-help@r-project.org<mailto:r-help@r-project.org>>
>> Subject: [R] About calculating average values from several matrices
>>
>> Hi R users,
>>
>> I have a question about manipulating the data.
>> For example, there are several such data frames or matrices, and I want to
>> calculate the average value from all the data frames or matrices. How to do
>> it? Also, should I convert them to data frame or matrix first? Right now,
>> when I use typeof() function, each one is a list.
>>
>> file1
>>             jan   feb   mar   apr   may   jun   jul   aug   sep   oct   nov
>>
>> app1   1.1   1.2    0.8    0.9   1.3    1.5   2.2   3.2   3.0    1.2   1.1
>> app2   3.1   3.2    2.8    2.5   2.3    2.5   3.2   3.0   2.9    1.8   1.8
>> app3   5.1   5.2    3.8    4.9   5.3    5.5   5.2   4.2   5.0    4.2   4.1
>>
>> file2
>>             jan   feb   mar   apr   may   jun   jul   aug   sep   oct   nov
>>
>> app1   1.9   1.5    0.5    0.9   1.2    1.8   2.5   3.7   3.2    1.5   1.6
>> app2   3.5   3.7    2.3    2.2   2.5    2.0   3.6   3.2   2.8    1.2   1.4
>> app3   5.5   5.0    3.5    4.4   5.4    5.6   5.3   4.4   5.2    4.3   4.2
>>
>> file3 has the similar structure and values...
>>
>> There are eight such files, and when I use the function mean(file1, file2,
>> file3, ..., file8), it returns the error below. Thanks for your help.
>>
>> Warning message:
>> In mean.default(file1, file2, file3, file4, file5, file6, file7,  :
>>   argument is not numeric or logical: returning NA
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org<mailto:R-help@r-project.org> mailing list -- To 
>> UNSUBSCRIBE and more, see
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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.
>>
>>
>>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org<mailto:R-help@r-project.org> mailing list -- To 
> UNSUBSCRIBE and more, see
> 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 -- To UNSUBSCRIBE and more, see
> 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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