3.1.2 Loops

Two types of loops exist in Scilab: the for loop and the while loop. The for loop steps through a vector of indices performing each time the commands delimited by end.

 
--> x=1;for k=1:4,x=x*k,end
 x         =
 
    1.  
 x         =
 
    2.  
 x         =
 
    6.  
 x         =
 
    24.

The for loop can iterate on any vector or matrix taking for values the elements of the vector or the columns of the matrix.

 
--> x=1;for k=[-1 3 0],x=x+k,end
 x         =
 
    0.  
 x         =
 
    3.  
 x         =
 
    3.

The for loop can also iterate on lists. The syntax is the same as for matrices. The index takes as values the entries of the list.

-->l=list(1,[1,2;3,4],'str')

-->for k=l, disp(k),end
 
    1.  
 
!   1.    2. !
!   3.    4. !
 
 str

The while loop repeatedly performs a sequence of commands until a condition is satisfied.

--> x=1; while x<14,x=2*x,end
 x         =
 
    2.  
 x         =
 
    4.  
 x         =
 
    8.  
 x         =
 
    16.

A for or while loop can be ended by the command break :

-->a=0;for i=1:5:100,a=a+1;if i > 10  then  break,end; end
 
-->a
 a  =
 
    3.

In nested loops, break exits from the innermost loop.

-->for k=1:3; for j=1:4; if k+j>4 then break;else disp(k);end;end;end
 
    1.  
 
    1.  
 
    1.  
 
    2.  
 
    2.  
 
    3.