Script files and editor in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a script file in MATLAB?

A script file is a text file containing a sequence of MATLAB commands. It runs these commands in order when executed, like a recipe for the computer.

beginner

How do you create a new script file in the MATLAB editor?

You can create a new script by clicking the 'New Script' button in the MATLAB editor toolbar or by typing edit('filename.m') in the command window.

beginner

Why is it important to save your script files with the .m extension?

MATLAB recognizes files with the .m extension as script or function files. Saving with this extension allows MATLAB to run the file as a program.

beginner

What happens when you run a script file in MATLAB?

When you run a script, MATLAB executes all the commands in the script one by one in the current workspace, affecting variables and showing results.

beginner

Name two features of the MATLAB editor that help you write scripts.

The MATLAB editor offers syntax highlighting (colors commands and keywords) and automatic indentation to make code easier to read and write.

What file extension should a MATLAB script file have?

A .txt

B .m

C .mat

D .exe

MATLAB script files must have the .m extension to be recognized and run by MATLAB.

Which MATLAB tool do you use to write and edit script files?

A Editor

B Workspace

C Command Window

D Figure Window

The Editor is the tool designed for writing and editing script files in MATLAB.

What happens when you run a script file in MATLAB?

A It executes commands in the script in order

B It deletes all variables

C It saves the script automatically

D It opens a new window

Running a script executes all commands inside it one by one.

How can you create a new script file quickly in MATLAB?

A Right-click Workspace

B Type <code>new</code> in Command Window

C Click 'New Script' button in Editor

D Use the Figure Window menu

Clicking 'New Script' in the Editor opens a blank script file for you to write code.

Why is syntax highlighting useful in the MATLAB editor?

A It changes the font size

B It saves the file automatically

C It runs the script faster

D It colors code to improve readability

Syntax highlighting colors different parts of code to make it easier to read and understand.

Explain what a MATLAB script file is and how you run it.

Think of a script as a list of instructions for MATLAB.

Describe two helpful features of the MATLAB editor when writing scripts.

These features help you see and organize your code better.

Practice

1. What is the main purpose of a script file in MATLAB?

easy

A. To create graphical user interfaces

B. To save and run a group of commands together

C. To store variables permanently

D. To compile MATLAB code into an executable

Solution

1. Step 1: Understand what script files do

   Script files contain a sequence of MATLAB commands saved in a file to run together.

2. Step 2: Compare options with script file purpose

   Only To save and run a group of commands together describes saving and running commands together, which is the main use of scripts.

3. Final Answer:

   To save and run a group of commands together -> Option B

4. Quick Check:

   Script files = save and run commands [OK]

Hint: Scripts group commands to run all at once [OK]

Common Mistakes:

• Confusing scripts with functions
• Thinking scripts store variables permanently
• Assuming scripts compile code

2. Which of the following is the correct way to save a script file in MATLAB Editor?

easy

A. Click File > Save or press Ctrl+S

B. Type save script in the command window

C. Right-click the command window and select Save

D. Use the command saveas('filename') in the script

Solution

1. Step 1: Identify how to save files in MATLAB Editor

   The Editor uses standard save options like File menu or Ctrl+S shortcut.

2. Step 2: Evaluate each option

   Only Click File > Save or press Ctrl+S correctly describes saving via Editor menu or shortcut. Others are incorrect or commands for different purposes.

3. Final Answer:

   Click File > Save or press Ctrl+S -> Option A

4. Quick Check:

   Save script = File menu or Ctrl+S [OK]

Hint: Use File menu or Ctrl+S to save scripts [OK]

Common Mistakes:

• Trying to save scripts from command window
• Using saveas command incorrectly
• Right-clicking command window instead of Editor

3. What will be the output when running this script in MATLAB Editor?

x = 5;
y = 3;
z = x + y;
disp(z);

medium

A. 8

B. 53

C. x + y

D. Error: Undefined variable

Solution

1. Step 1: Understand the script commands

   Variables x and y are assigned 5 and 3, then z is sum of x and y.

2. Step 2: Calculate the value of z and output

   z = 5 + 3 = 8, disp(z) prints 8 to the command window.

3. Final Answer:

   8 -> Option A

4. Quick Check:

   5 + 3 = 8 output [OK]

Hint: Add variables then display result [OK]

Common Mistakes:

• Concatenating numbers as strings
• Expecting variable names printed
• Assuming error without variable initialization

4. Identify the error in this MATLAB script:

for i = 1:3
  disp(i)
endd

medium

A. disp function used incorrectly

B. Missing semicolon after disp(i)

C. Loop variable i is not defined

D. Incorrect end keyword spelling

Solution

1. Step 1: Check the loop syntax

   The for loop uses 'endd' instead of 'end' to close the loop.

2. Step 2: Identify the syntax error

   MATLAB requires 'end' keyword exactly; 'endd' causes a syntax error.

3. Final Answer:

   Incorrect end keyword spelling -> Option D

4. Quick Check:

   Loop ends with 'end' keyword [OK]

Hint: Use exact 'end' to close loops [OK]

Common Mistakes:

• Typing 'endd' instead of 'end'
• Forgetting to close loops
• Adding unnecessary semicolons

5. You want to create a script that calculates the average of numbers stored in a vector data. Which script structure correctly computes and displays the average?

hard

A. avg = mean(data)
disp(total);

B. for i = 1:length(data)
avg = data(i) / length(data);
end
disp(avg);

C. total = sum(data);
count = length(data);
avg = total / count;
disp(avg);

D. avg = sum(data) * length(data);
disp(avg);

Solution

1. Step 1: Understand how to calculate average

   Average = sum of elements divided by number of elements.

2. Step 2: Check each script option

   total = sum(data);
   count = length(data);
   avg = total / count;
   disp(avg);

   correctly sums data, counts elements, divides, then displays average. Others have errors: A displays undefined total, C overwrites avg incorrectly in loop, D multiplies instead of dividing.

3. Final Answer:

   total = sum(data); count = length(data); avg = total / count; disp(avg); -> Option C

4. Quick Check:

   Average = sum / count [OK]

Hint: Average = sum divided by count, then display [OK]

Common Mistakes:

• Using mean without displaying correct variable
• Calculating average inside loop incorrectly
• Multiplying sum by length instead of dividing