MATLAB: How to append data for a variable column in a matrix

concatenationfor loopmatrix

I load an excel sheet using xlsread command. The excel sheet can have any number of rows and columns.
Example of the matrix (3*2)from the excel sheet will look like this:
System Code
AEA AEA00
AW WP000
The above matrix can have any length. Based on the column dimension, I want to concatenate the rows with a '-'. For e.g. the second row after concatenation can look like AEA-AEA00.
Could you suggest a way out for implementing the same?

Best Answer

Assuming
 D = {'AEA', 'AEA00'; 'AW', 'WP000'}
you can concatenate e.g. row 1 with
 >> sprintf( '%s-', D{1,:} )
 ans =
       AEA-AEA00-
and remove the last dash afterwards. For performing this on the whole array:
 nRows = size( D, 1 ) ;
 Dcat  = cell( nRows, 1 ) ;
 for k = 1 : nRows
    tmp = sprintf( '%s-', D{k,:} ) ;
    Dcat{k} = tmp(1:end-1) ;
 end
This works with an arbitrary number of rows and columns. In the present case, it outputs
 >> Dcat
 Dcat = 
    'AEA-AEA00'
    'AW-WP000'
Notes:
  • You might want to truncate the first row if it contains 'System Code'.
  • This solution assumes that each row has the same number of non-empty columns. Let me know if it isn't the case; it is easy to add a line which selects only non-empty cells before the call to SPRINTF.
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