MATLAB - Commands

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MATLAB is an interactive program for numerical computation and data visualization. You can enter a command by typing it at the MATLAB prompt '>>' on the Command Window.

In this section, we will provide lists of commonly used general MATLAB commands.

Commands for Managing a Session

MATLAB provides various commands for managing a session. The following table provides all such commands:

CommandPurpose
clc Clears command window.
clear Removes variables from memory.
existChecks for existence of file or variable.
globalDeclares variables to be global.
helpSearches for a help topic.
lookforSearches help entries for a keyword.
quitStops MATLAB.
whoLists current variables.
whosLists current variables (long display).

Commands for Working with the System

MATLAB provides various useful commands for working with the system, like saving the current work in the workspace as a file and loading the file later.

It also provides various commands for other system-related activities like, displaying date, listing files in the directory, displaying current directory, etc.

The following table displays some commonly used system-related commands:

CommandPurpose
cd Changes current directory.
dateDisplays current date.
deleteDeletes a file.
diarySwitches on/off diary file recording.
dirLists all files in current directory.
loadLoads workspace variables from a file.
pathDisplays search path.
pwdDisplays current directory.
saveSaves workspace variables in a file.
typeDisplays contents of a file.
whatLists all MATLAB files in the current directory.
wklread Reads .wk1 spreadsheet file.

Input and Output Commands

MATLAB provides the following input and output related commands:

CommandPurpose
disp Displays contents of an array or string.
fscanf Read formatted data from a file.
formatControls screen-display format.
fprintfPerforms formatted writes to screen or file.
inputDisplays prompts and waits for input.
;Suppresses screen printing.

The fscanf and fprintf commands behave like C scanf and printf functions. They support the following format codes:

Format CodePurpose
%s Format as a string.
%d Format as an integer.
%f Format as a floating point value.
%e Format as a floating point value in scientific notation.
%g Format in the most compact form: %f or %e.
\n Insert a new line in the output string.
\t Insert a tab in the output string.

The format function has the following forms used for numeric display:

Format Function Display up to
format short Four decimal digits (default).
format long 16 decimal digits.
format short eFive digits plus exponent.
format long e16 digits plus exponents.
format bankTwo decimal digits.
format +Positive, negative, or zero.
format ratRational approximation.
format compactSuppresses some line feeds.
format looseResets to less compact display mode.

Vector, Matrix and Array Commands

The following table shows various commands used for working with arrays, matrices and vectors:

CommandPurpose
cat Concatenates arrays.
find Finds indices of nonzero elements.
length Computes number of elements.
linspace Creates regularly spaced vector.
logspace Creates logarithmically spaced vector.
max Returns largest element.
min Returns smallest element.
prod Product of each column.
reshape Changes size.
size Computes array size.
sort Sorts each column.
sum Sums each column.
eye Creates an identity matrix.
ones Creates an array of ones.
zeros Creates an array of zeros.
cross Computes matrix cross products.
dot Computes matrix dot products.
detComputes determinant of an array.
inv Computes inverse of a matrix.
pinv Computes pseudoinverse of a matrix.
rank Computes rank of a matrix.
rref Computes reduced row echelon form.
cell Creates cell array.
celldisp Displays cell array.
cellplot Displays graphical representation of cell array.
num2cell Converts numeric array to cell array.
deal Matches input and output lists.
iscell Identifies cell array.

Plotting Commands

MATLAB provides numerous commands for plotting graphs. The following table shows some of the commonly used commands for plotting:

CommandPurpose
axis Sets axis limits.
fplot Intelligent plotting of functions.
grid Displays gridlines.
plot Generates xy plot.
print Prints plot or saves plot to a file.
title Puts text at top of plot.
xlabel Adds text label to x-axis.
ylabel Adds text label to y-axis.
axes Creates axes objects.
close Closes the current plot.
close all Closes all plots.
figure Opens a new figure window.
gtext Enables label placement by mouse.
hold Freezes current plot.
legend Legend placement by mouse.
refresh Redraws current figure window.
set Specifies properties of objects such as axes.
subplot Creates plots in subwindows.
text Places string in figure.
bar Creates bar chart.
loglog Creates log-log plot.
polar Creates polar plot.
semilogx Creates semilog plot. (logarithmic abscissa).
semilogy Creates semilog plot. (logarithmic ordinate).
stairs Creates stairs plot.
stem Creates stem plot.


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