Concatenate vectors or matrices under Matlab

Concatenation of variables Matlab is define as the combination these variables in a single (vector or matrix).

Example:

       	  | 2 3 4 | 
X = 	| 1 2 5 | 
       	  | 0 2 7 | 

With:

       	  | 9 6 8 | 
Y = 	| 5 6 2 | 
      	  | 3 2 1 | 

(concatenation of rows):

                   | 9 6 8 2 3 4 | 
Result =	| 1 2 5 5 6 2 | 
              	   | 0 2 7 3 2 1 | 
 

Or (concatenation of columns):

          	  | 2 3 4 | 
          	  | 1 2 5 | 
          	  | 0 2 7 | 
Result =       | 9 6 8 | 
       	          | 5 6 2 | 
       	          | 3 2 1 | 

From here you may have noticed that not all variables can be concatenate.

Horizontal concatenation

Using X and Y (they can be vectors, matrices or simple variable). It is necessary that the two variables to concatenate have the same number of rows. The code is as follows:

Result = [X Y]

Vertical concatenation

Using X and Y (they can be vectors, matrices or simple variable). It is necessary that the two variables to concatenate have the same number of columns. The code is as follows:

Result = [X, Y]

Further calculations

• Option 1

You can concatenate a vector (matrix) with the transposed of the other. For example:

X = | 1 2 | 

       | 2 | 
Y =  | 3 | 
       | 5 | 

Using the command:

Result = [X Y] 

Result = | 1 2 2 3 5 |

Using the command:

Result = [X ', Y] 

               | 1 | 
               | 2 | 
Result =   | 2 | 
               | 3 | 
               | 5 | 

• Option 2

The principle remains the same, we can concatenate multiple variables, provided the scale is respected.

For example. Using the following set of variable:

A = 1 
B = 2 
C = | 3 4 | 
       | 5 6 | 
D = 7 
E = | 8 9 | 

The command:

Result = [[A;B] C;D E]

             | 1 3 4 | 
Result =  | 2 5 6 | 
             | 7 8 9 |