![]() ![]() MATLAB rand function MATLAB ones function MATLAB zeros function MATLAB eye function MATLAB diag function MATLAB get diag function diag() function can be used to create a diagonal matrix or to get diagonal elements of a matrix. eye() function is used to create identity matrix. Ones() and zeros() can be used to create an array of all ones and an array of all zeros. We can quickly create a square or non-square matrix using random numbers. > even_col = even_row' Vector and Matrix Creation Functions How can we create column vectors? We can create column vectors manually, by entering the elements and separating them by a semicolon.Īnother method is to create a row vector using one of the shorthand methods discussed before and then use the transpose operator to create a column vector. > even_row = linspace(0, 1, 5) creates a row vector with 5 elements evenly spaces from 0 to 1. We must specify the number of elements we want in a vector. > even_row = 1 : 0.5 : 5 creates a row vector with elements 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0.Īnother method to create evenly spaced vectors is the linspace() function. We can specify different spacing using the colon operator. a*b must equal x*y for this to work.The colon operator uses a default spacing of 1. It takes a matrix M that used to have x rows and y columns and turns it into a matrix with a rows and b columns. With a matrix, diag pulls out the diagonal elements and makes a vector out of them. See in the snippet below a successful deletion of the fourth element of a vector, and what happens when I try to delete just one element from a 4x3 matrix.Ī null assignment can have only one non-colon index.ĭiag on a vector creates a matrix whose diagonal is the initial vector and whose other elements are zero. Using empty brackets to delete elements from a matrix works if you are going to delete a whole row or a whole column, but not just one element. Deleting is not the same as assigning zero to the value of that element. Use empty brackets to delete an element from a vector or a row/column from a matrix. To append vectors to a matrix you need to make sure the dimensions work out so that all rows have the same number of elements. If it is not the next consecutive position, MATLAB pads the elements in between with zeros. To append an element to a vector just specify a value at the desired position. ![]() M(,) addresses the intersection of rows a and b and columns c through d and e. For example v() addresses elements a, b, and c through d. Use a square bracket to address nonconsecutive elements in a vector or matrix. M(:,a) addresses column a, M(a,:) addresses row a, M(:,a:b) addresses columns a through b, M(a:b,:) addresses rows a through b, M(a:b,c:d) addresses the intersection of rows a through b and columns c through d. For example, v(:) addresses all the elements of a vector, v(a:b) addresses elements a through b in vector v. Use the colon operator to address a range of elements in a vector or matrix. It's just like playing Battleship except both the columns and rows are designated by numbers. Then I ask it for the element in the second row and third column. In the example below I make a 3x3 matrix M. M(1,1) addresses the element in the top left corner of the matrix M. For example, v(1) addresses the first element in a vector v. You can also use that technique to address a specific spot in a matrix. We've already practiced using parentheses to address a certain element of a vector.
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