Concatenate two strings in one in a string matrix

Dear R-Users

I have the following matrix

out$desc      [,1]            [,2]

[1,] ""              ""
[2,] "y_{01}(k-001)" ""
[3,] "y_{01}(k-002)" ""
[4,] "y_{01}(k-003)" ""
[5,] "u_{01}(k-001)" ""
[6,] "u_{01}(k-002)" ""
[7,] "u_{01}(k-003)" ""
[8,] "y_{01}(k-001)" "y_{01}(k-001)"
[9,] "y_{01}(k-001)" "y_{01}(k-002)"
[10,] "y_{01}(k-001)" "y_{01}(k-003)"
[11,] "y_{01}(k-001)" "u_{01}(k-001)"


and need to concatenate each line to a single string.  Something like

[2,] "y_{01}(k-001)" ""  -> [2,] "y_{01}(k-001)"

[11,] "y_{01}(k-001)" "u_{01}(k-001)" -> [11,] "y_{01}(k-001)*u_{01} 
(k-001)"

Is there a way to do it without going through every column?

Hello

Many thanks.

* is not a typo.   The output is a description of a nonlinear system  
so terms such as y(k-1)*y(k-2) are allowed.   I wonder whether ""  
could be ignored so that the outputs such as y_{01}(k-003)* would  
not show up.

Cheers

Ed


On Thu, Aug 18, 2011 at 3:40 PM, David Winsemius <dwinsemius at comcast.net 

wrote:

On Aug 18, 2011, at 2:35 PM, Eduardo Mendes wrote:

Dear R-Users

I have the following matrix

out$desc      [,1]            [,2]
[1,] ""              ""
[2,] "y_{01}(k-001)" ""
[3,] "y_{01}(k-002)" ""
[4,] "y_{01}(k-003)" ""
[5,] "u_{01}(k-001)" ""
[6,] "u_{01}(k-002)" ""
[7,] "u_{01}(k-003)" ""
[8,] "y_{01}(k-001)" "y_{01}(k-001)"
[9,] "y_{01}(k-001)" "y_{01}(k-002)"
[10,] "y_{01}(k-001)" "y_{01}(k-003)"
[11,] "y_{01}(k-001)" "u_{01}(k-001)"


and need to concatenate each line to a single string.  Something like

[2,] "y_{01}(k-001)" ""  -> [2,] "y_{01}(k-001)"

[11,] "y_{01}(k-001)" "u_{01}(k-001)" -> [11,] "y_{01}(k-001)*u_{01} 
(k-001)"

Is there a way to do it without going through every column?

apply(out$desc, 1, paste, collapse="")

It is ambiguous what you want for a delimiter. In one case you used  
"", and another you used "*". I used "".


-- 

David Winsemius, MD
West Hartford, CT

On Aug 19, 2011, at 9:45 AM, Eduardo Mendes wrote:

Hello

Many thanks.

* is not a typo.   The output is a description of a nonlinear  
system so terms such as y(k-1)*y(k-2) are allowed.   I wonder  
whether "" could be ignored so that the outputs such as y_{01} 
(k-003)* would not show up.

Paste with "*"  then remove trailing "*"'s:

ifelse( grepl("*$", result), sub("*","", result), result)