[R] how to create column names for the matrix

[Hervé Pagès]

On 07/27/2016 11:49 AM, lily li wrote:
> If replace 1:5 to char2 = c('east','west','south','north','central'),
> how to put on column names with the original structure? Thanks again.

Have you tried to actually "replace 1:5 with char2", literally?

You need to try things before you ask. That's the only way to learn!

H.

>
>
> On Wed, Jul 27, 2016 at 12:40 PM, Hervé Pagès <hpages at fredhutch.org
> <mailto:hpages at fredhutch.org>> wrote:
>
>     Hi,
>
>
>     On 07/27/2016 11:17 AM, lily li wrote:
>
>         Hi all,
>
>         I want to ask that how to create column names for a matrix. For
>         example,
>         the matrix below, the column names should be: 1-A, 1-B, 1-C,
>         1-D, 2-A, 2-B,
>         2-C, 2-D, 3-A, etc. Thanks for your help.
>
>         chars = c('A','B','C','D')
>         matrix1 = matrix(nrow = length(1:100), ncol =
>         length(1:5)*length(chars))
>         k = 0
>         for(i in seq(1:length(1:5))){
>           for(j in seq(1:length(chars))){
>             k = k+1
>             matrix1[,k] = c(1:100)[k]
>           }
>         }
>
>
>     Also how could you possibly use such level of code obfuscation to
>     perform such simple initialization of your matrix?
>
>     My 1st advice would be that you slow down and take the time to compare
>     seq(1:length(1:5)) with 1:length(1:5) with 1:5. It will be a great
>     learning experience!
>
>     As for initializing your matrix, what about doing
>
>       ncol <- 5 * length(chars)
>       matrix1 <- matrix(seq_len(ncol), nrow=100, ncol=ncol, byrow=TRUE)
>
>     instead?
>
>     Then set the colnames with:
>
>       colnames(matrix1) <- paste(rep(1:5, length(chars)), chars, sep="-")
>
>     Cheers,
>     H.
>
>
>                 [[alternative HTML version deleted]]
>
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>
>
>     --
>     Hervé Pagès
>
>     Program in Computational Biology
>     Division of Public Health Sciences
>     Fred Hutchinson Cancer Research Center
>     1100 Fairview Ave. N, M1-B514
>     P.O. Box 19024
>     Seattle, WA 98109-1024
>
>     E-mail: hpages at fredhutch.org <mailto:hpages at fredhutch.org>
>     Phone:  (206) 667-5791 <tel:%28206%29%20667-5791>
>     Fax:    (206) 667-1319 <tel:%28206%29%20667-1319>
>
>

-- 
Hervé Pagès

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpages at fredhutch.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319