Commands in Matlab session

• Command                   Description
• CLC                           clearing of command window.
• CLOSE ALL             Closes all plots.
• CLEAR                       variables removed from the memory.
• HELP                         Searches for a topic you need.
• EXIST                        command used to check for the availability of file or variable.
• GLOBAL                   Declaration of variables as global.
• QUIT                          Stops MATLAB session.
• EPS                                Defining accuracy of floating-point precision.
• INF                              defined for Infinity.
• NAN                           not defining a numerical result (not a number).
• Pi                                The number p.
• Cd                               useful for changing the current directory.
• DATE                         present day date is displayed.
• DELETE                         useful for deleting a File.
• PRINT                             Prints a plot.
• AXIS                                Sets axis limits.
• GRID                         Gridlines will be displayed.
• PLOT                         plots of x and y axis will be displayed.
• PRINT                        Prints the plots and saved it to file.
• TITLE                        To provide text on top of plot.
• X-LABEL                  x-axis is added with labels.
• Y-LABEL                  y-axis is added with labels.
• HOLD                             fix the current plot.
• FIGURE                    new figure window is created.
• SUBPLOT                 shows plots in subwindows.
• STEM                         shows stem plot
• ONES                          Creates an array of ones.
• ZEROS                        A zero array is created.
• %s Format as a string.
• %d                               Format as an integer.
• %f  Format as a floating point value.

• \n                          enter a new line in the output string.
• \t                           In order to insert a tab in the output string.
• [ ]                                     Brackets; enclosures array elements.
• .                                               Symbol is used to define decimal point.
• +                                      Addition operation
• –                                               Subtraction operation.
• *                                              performs Scalar and matrix multiplication.
• INPUT                            Waits for input by displaying prompt.
• RESHAPE                      used to change size.
• DET                                perform determinant of an array.
• INV                                 perform inverse of a matrix.
• RAND                           Distributed random elements uniformly.
• RANDN                         Random elements will be distributed normally.

DELETING ROWS AND COLUMNS:

              Pair of square brackets useful for performing deleting row and column operation. Let begin with

 A = D;

 In order to delete the second column of A, let use the equation as shown

 A (:, 2) = []

This changes A to A = 16    2    13

                                      5     11    8

                                       9     7     12

                                      4     14     1

If you will delete any one element from a matrix, the result will not anymore a matrix. So, expressions like

A (1, 2) = []

 Result in an error. From the above operation we know how to delete a single element, or sequence of elements, and how to change the remaining shape of the elements into a row vector.

So A(2:2:10) = []

Results in X = 1   6   9   2   7    13   12   1

DATA TYPES IN MATLAB:

With the help of different types of data types or classes you can work with you code by creating arrays, table, matrices, floating-point and so on. Matlab combines integers, floats and booleans into one thing: doubles or floating point number.

 Example: >> a = 1.54 % this is a double

                  >> b = a > 1 % Logical (Boolean) double.

Strings. Character arrays will be treated as string matlab.

>>b = ‘abcd’ % NOTE that matlab uses single quotes

>>b (2:3)

Arrays/Matrices of numbers. In order to separate rows we use this operator ‘;‘, or same goes with blank space to separate columns ‘,’.

a= [4 5 6; 1, 2, 3].

Cell array is way to store mixed data or several strings.

d = {‘abcd’, 1, [123], ‘def’

There are 16 fundamental classes in MATLAB. Most of the classes are in the form of an array or a matrix. With the exception of function handles, this matrix or array starts with a minimum of zero in size and it will grow to an n-dimensional array of maximum size. A function will always handle in scalar matrix.