Consider the following loops: ch = 'abc' ĭisp() % NUM2STR converts the number stored in k to a charachter, Loops can be nested, to preform iterated task within another iterated task. For example, the above loop can be replaced by my_vector = my_vector + 1. Most simple things done with for loops can be done faster and easier by vectorized operations. each column of the iterated matrix displayed, each column printed on each call of display. (The row vector version is a normal case of this, because in Matlab a row vector is just a matrix whose columns are size 1.) If the right-hand side of the assignment is a matrix, then in each iteration the variable is assigned subsequent columns of this matrix.
FOR LOOPS MATLAB CODE
Hence, the two following blocks of code are identical: A = Īnd the following are identical as well: A = Īny row vector will do. (The 1:n version is a normal case of this, because in Matlab 1:n is just syntax for constructing a row vector of. The for loop assigns a different element of this vector to the variable each run. The left-hand side of the assignment can be any valid variable name. The right-hand side of the assignment in a for loop can be any row vector. This time we use both the n and k in the loop, to create a "nested" display: 5 4 3 2 1 The loop will execute the inner statement(s), everything between the for and the end, for n times (5 in this example): 1ĭisp(n-k+1:-1:1) % DISP uses more "clean" way to print on the screen Say we want to display the numbers between 1 to n, we can write: n = 5 The simplest case is just preforming a task for a fixed known number of times. This can be detected by slightly altering the syntax. For performance reasons, Matlab actually treats any a:b or a:c:b specially by not creating the row vector entirely, but instead creating each element one at a time.
The basic example treats 1:n as a normal instance of creating a row vector and then iterating over it.
Special case performance of a:b in right-hand side
I = 5 % Fail at trying to terminate the loop % Prints once: Īltering the iteration variable changes its value for the current iteration, but has no impact on its value in subsequent iterations. (There is actually no distinction in Matlab.) The for loop runs once with the loop variable set to the column. A column vector is treated like a matrix with one column. A common source of bugs is trying to loop over the elements of a column vector.