MATLAB Cheatsheet - MATLAB Commands & Matrix Operations Reference

This reference is for engineers and scientists who think in matrices rather than element loops. It covers building matrices and vectors, in-place operations like transpose and eigenvalue decomposition, statistical summaries, plotting curves and surfaces, file read/write, and FFT-based signal analysis. Unlike numpy the commands here feel native to the language, so you can type them directly in the Command Window and inspect each result. After reading you should be able to assemble a matrix, transpose/invert/decompose it, turn a vector into a plot, and save the intermediate result with save/load.

Languages·83 commands·Last updated 2026-07-21

Matrix Creation 8

A = [1 2 3; 4 5 6; 7 8 9]

Create a 3x3 matrix

B = [1; 2; 3]

Create a column vector

C = [1, 2, 3]

Create a row vector

D = zeros(3, 4)

Create a 3x4 zero matrix

E = ones(2, 3)

Create a 2x3 ones matrix

F = eye(3)

Create a 3x3 identity matrix

G = rand(3, 3)

Create a 3x3 random matrix

H = linspace(0, 10, 100)

100 evenly spaced points from 0 to 10

Matrix Operations 11

A'

Matrix transpose

inv(A)

Matrix inverse

det(A)

Matrix determinant

rank(A)

Matrix rank

trace(A)

Matrix trace (sum of diagonal)

eig(A)

Eigenvalues and eigenvectors

svd(A)

Singular value decomposition

A * B

Matrix multiplication

A .* B

Element-wise multiplication

A / B

Right division (A * inv(B))

A \ B

Left division (inv(A) * B)

Data Visualization 16

plot(x, y)

Plot a 2D curve

scatter(x, y)

Scatter plot

bar(x, y)

Bar chart

hist(data)

Histogram

pie(data)

Pie chart

surf(X, Y, Z)

3D surface plot

mesh(X, Y, Z)

3D mesh plot

contour(X, Y, Z)

Contour plot

title("Chart Title")

Set the chart title

xlabel("X Axis")

Set the X-axis label

ylabel("Y Axis")

Set the Y-axis label

legend("Curve 1", "Curve 2")

Add a legend

grid on

Show grid

hold on

Hold the current figure and keep drawing

hold off

Release the figure hold

subplot(2, 2, 1)

Create the 1st of a 2x2 subplot grid

Data Processing 12

mean(A)

Compute the mean

median(A)

Compute the median

std(A)

Compute the std deviation

var(A)

Compute the variance

max(A)

Compute the max

min(A)

Compute the min

sum(A)

Compute the sum

cumsum(A)

Compute the cumulative sum

diff(A)

Compute differences

sort(A)

Sort

unique(A)

Unique values

find(A > 5)

Find indices meeting a condition

File I/O 10

load("data.mat")

Load a MAT file

save("data.mat", "var")

Save variables to a MAT file

data = csvread("file.csv")

Read a CSV file

csvwrite("file.csv", data)

Write a CSV file

data = xlsread("file.xlsx")

Read an Excel file

xlswrite("file.xlsx", data)

Write an Excel file

fid = fopen("file.txt", "r")

Open a text file

fclose(fid)

Close a file

fscanf(fid, "%f", [1, inf])

Read file contents

fprintf(fid, "%f\n", data)

Write file contents

Programming Basics 10

for i = 1:10 ... end

for loop

while condition ... end

while loop

if condition ... elseif ... else ... end

Conditional (if/elseif/else)

switch expr case val1 ... otherwise ... end

switch statement

function [out] = func(in) ... end

Define a function

% comment

Single-line comment

%{ block comment %}

Block comment

disp("message")

Display a message

fprintf("format %d\n", var)

Formatted output

input("Prompt: ")

User input

Linear Algebra 9

A * x = b

Solve a linear system

x = A \ b

Solve via left division

[L, U, P] = lu(A)

LU decomposition

[Q, R] = qr(A)

QR decomposition

[U, S, V] = svd(A)

SVD

norm(A)

Matrix norm

cond(A)

Condition number

null(A)

Null space basis

orth(A)

Orthogonal basis

Signal Processing 7

fft(x)

Fast Fourier transform

ifft(X)

Inverse FFT

conv(x, y)

Convolution

xcorr(x, y)

Cross-correlation

filter(b, a, x)

Digital filtering

spectrogram(x)

Spectrogram

psd(x)

Power spectral density

Tips

MATLAB indices start at 1, not 0 (unlike Python/C).
Matrix multiply uses *; element-wise uses .* - keep them distinct.
plot connects points into a curve; scatter draws individual points.
hold on overlays multiple curves on one figure; hold off releases it.
load/save default to MAT format; use csvread/csvwrite for CSV.
A function file must match the function name, e.g. myfunc.m for function myfunc.
Use help to view function docs, e.g. help plot.
Use doc to open full documentation, e.g. doc plot.

Official References

Each command links to its official documentation below, so you can verify the latest usage and read deeper.

Official Docs

Maintained by LaoHand

Publicly updated on Jul 21, 2026, continuously proofread against official docs.

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