[R] apply and cor()

[Micha Silver]

On 05/12/2017 06:53 PM, David L Carlson wrote:
> Actually, not using apply() would be faster and simpler
>
> cor(t(compare_data), t(test_data))
Worked just as I wanted, thanks!
I first reshaped the data frames, then I didn't even need the t()
>
> David C
>
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of David L Carlson
> Sent: Friday, May 12, 2017 10:48 AM
> To: Ismail SEZEN <sezenismail at gmail.com>; Micha Silver <tsvibar at gmail.com>
> Cc: R-help at r-project.org
> Subject: Re: [R] apply and cor()
>
> Actually, r is a vector, not an index value. You need
>
> apply(compare_data, 1, function(r) cor(r, t(test_data)))
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
>
>
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ismail SEZEN
> Sent: Friday, May 12, 2017 10:11 AM
> To: Micha Silver <tsvibar at gmail.com>
> Cc: R-help at r-project.org
> Subject: Re: [R] apply and cor()
>
>
>> On 12 May 2017, at 17:57, Micha Silver <tsvibar at gmail.com> wrote:
>>
>> I have two data.frames, one with a single row of 31 columns, and the second with 269 rows and the same 31 columns.
>>> dim(compare_data)
>> [1] 269  31
>>> dim(test_data)
>> [1]  1 31
>>
>> I want to apply cor() between the one row of 'test_data', and each row of the 'compare_data' .
>> I tried 'apply' but I get this error:
>>> apply(compare_data, 1, function(r) {cor(compare_data[r,], test_data)})
>> Error in cor(compare_data[r, ], test_data) : incompatible dimensions
>
> apply(compare_data, 1, function(r) {cor(compare_data[r,], as.numeric(test_data))})
>
> See ?cor. Explanation of y is "NULL (default) or a vector, matrix or data frame with compatible dimensions to x”.
>
>>
>> In order to try to understand I did:
>>> dims <- apply(compare_data, 1, function(r) {dim(compare_data[r,])})
>>> head(dims)
>>      20 73 103 118 130 142 151 154 191 205 217 222 227 232 240 275 282 301 320 359 360 551 589 653 789 801 808 812
>> [1,]  9  8   8   9   5   9   8  11   6  15  12  13  10   7   9  14 8  11   9  11  11  12   9  14   5   8   9  10
>> [2,] 31 31  31  31  31  31  31  31  31  31  31  31  31  31  31  31 31  31  31  31  31  31  31  31  31  31  31  31
>>      840 856 857 867 885 970 983 985 1103 1107 1197 1207 1237 1262 1279 1282 1332 1357 1358 1392 1411 1435 1458 1473
>> [1,]  14  11  12   8  10   2   7   9   10    8   10   13   11 7    9   12   11   11   16   10   10   12   10   10
>> [2,]  31  31  31  31  31  31  31  31   31   31   31   31   31   31 31   31   31   31   31   31   31   31   31   31
>>
>> and indeed I am getting different row dimensions. I expected "1 31" for each. What are the values 9,8,8,9,5... in the [1,] dimension?
>>
>> If I test the compare_data data.frame one row at a time:
>>> dim(compare_data['20',])
>> [1]  1 31
>>> dim(compare_data['1473',])
>> [1]  1 31
>>
>> It looks as I expected.
>> What am I missing??
>>
>> Thanks
>>
>> -- 
>> Micha Silver
>> cell: +972-523-665918
>>
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>
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>
> ______________________________________________
> R-help at 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.
> ______________________________________________
> R-help at 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.

-- 
Micha Silver
cell: +972-523-665918