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 −
Command |
Purpose |
clc |
Clears command window. |
clear |
Removes variables from memory. |
exist |
Checks for existence of file or variable. |
global |
Declares variables to be global. |
help |
Searches for a help topic. |
lookfor |
Searches help entries for a keyword. |
quit |
Stops MATLAB. |
who |
Lists current variables. |
whos |
Lists 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 −
Command |
Purpose |
cd |
Changes current directory. |
date |
Displays current date. |
delete |
Deletes a file. |
diary |
Switches on/off diary file recording. |
dir |
Lists all files in current directory. |
load |
Loads workspace variables from a file. |
path |
Displays search path. |
pwd |
Displays current directory. |
save |
Saves workspace variables in a file. |
type |
Displays contents of a file. |
what |
Lists 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 −
Command |
Purpose |
disp |
Displays contents of an array or string. |
fscanf |
Read formatted data from a file. |
format |
Controls screen-display format. |
fprintf |
Performs formatted writes to screen or file. |
input |
Displays 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 Code |
Purpose |
%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 e |
Five digits plus exponent. |
format long e |
16 digits plus exponents. |
format bank |
Two decimal digits. |
format + |
Positive, negative, or zero. |
format rat |
Rational approximation. |
format compact |
Suppresses some line feeds. |
format loose |
Resets to less compact display mode. |
Vector, Matrix and Array Commands
The following table shows various commands used for working with arrays, matrices and vectors −
Command |
Purpose |
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. |
det |
Computes 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 −
Command |
Purpose |
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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