Commands

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
clcClears command window.
clearRemoves 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
cdChanges 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.
wklreadReads .wk1 spreadsheet file.

Input and Output Commands

MATLAB provides the following input and output related commands −

CommandPurpose
dispDisplays contents of an array or string.
fscanfRead 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
%sFormat as a string.
%dFormat as an integer.
%fFormat as a floating point value.
%eFormat as a floating point value in scientific notation.
%gFormat in the most compact form: %f or %e.
\nInsert a new line in the output string.
\tInsert a tab in the output string.

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

Format FunctionDisplay up to
format shortFour decimal digits (default).
format long16 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
catConcatenates arrays.
findFinds indices of nonzero elements.
lengthComputes number of elements.
linspaceCreates regularly spaced vector.
logspaceCreates logarithmically spaced vector.
maxReturns largest element.
minReturns smallest element.
prodProduct of each column.
reshapeChanges size.
sizeComputes array size.
sortSorts each column.
sumSums each column.
eyeCreates an identity matrix.
onesCreates an array of ones.
zerosCreates an array of zeros.
crossComputes matrix cross products.
dotComputes matrix dot products.
detComputes determinant of an array.
invComputes inverse of a matrix.
pinvComputes pseudoinverse of a matrix.
rankComputes rank of a matrix.
rrefComputes reduced row echelon form.
cellCreates cell array.
celldispDisplays cell array.
cellplotDisplays graphical representation of cell array.
num2cellConverts numeric array to cell array.
dealMatches input and output lists.
iscellIdentifies cell array.

Plotting Commands

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

CommandPurpose
axisSets axis limits.
fplotIntelligent plotting of functions.
gridDisplays gridlines.
plotGenerates xy plot.
printPrints plot or saves plot to a file.
titlePuts text at top of plot.
xlabelAdds text label to x-axis.
ylabelAdds text label to y-axis.
axesCreates axes objects.
closeCloses the current plot.
close allCloses all plots.
figureOpens a new figure window.
gtextEnables label placement by mouse.
holdFreezes current plot.
legendLegend placement by mouse.
refreshRedraws current figure window.
setSpecifies properties of objects such as axes.
subplotCreates plots in subwindows.
textPlaces string in figure.
barCreates bar chart.
loglogCreates log-log plot.
polarCreates polar plot.
semilogxCreates semilog plot. (logarithmic abscissa).
semilogyCreates semilog plot. (logarithmic ordinate).
stairsCreates stairs plot.
stemCreates stem plot.

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