Function handles in MATLAB - Step-by-Step Execution

Concept Flow - Function handles

Define function handle

↓

Store function reference

↓

Call function via handle

↓

Execute function code

↓

Return result

Create a function handle to refer to a function, then call it through the handle to run the function and get results.

Execution Sample

MATLAB

f = @(x) x^2;
result = f(3);

Defines a function handle f that squares input x, then calls f with 3 to get 9.

Execution Table

Step	Action	Evaluation	Result
1	Define function handle f = @(x) x^2	f is a handle to anonymous function	f stores reference to function
2	Call f(3)	Compute 3^2	9 assigned to result
3	End	No more code	Execution stops

💡 No more statements to execute, program ends

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
f	undefined	function handle @(x) x^2	function handle @(x) x^2	function handle @(x) x^2
result	undefined	undefined	9	9

Key Moments - 2 Insights

Why do we use '@' when defining a function handle?

The '@' symbol tells MATLAB to create a function handle, not call the function immediately. See execution_table step 1 where f is assigned the handle.

What happens when we call f(3)?

Calling f(3) runs the function code with x=3, computing 3^2=9, as shown in execution_table step 2.

Visual Quiz - 3 Questions

Look at the execution table, what is stored in variable 'f' after step 1?

A The number 3

B The result 9

C A function handle to square a number

D Undefined

💡 Hint

Check variable_tracker row for 'f' after step 1

At which step is the function actually executed?

A Step 1

B Step 2

C Step 3

D Never

💡 Hint

Look at execution_table action 'Call f(3)'

If we change the input to f(4), what would be the new result in 'result' variable?

A 16

B 7

C 8

D 4

💡 Hint

Recall the function squares the input, see execution_table step 2

Concept Snapshot

Function handles in MATLAB:
- Use '@' to create a handle: f = @(x) expression;
- The handle stores a reference to the function code
- Call the function via handle: result = f(value);
- The function executes when called, returning output
- Useful for passing functions as arguments or storing them

Full Transcript

In MATLAB, a function handle is created using the '@' symbol followed by the function input and expression. This handle stores a reference to the function without running it immediately. When you call the handle with an input, MATLAB executes the function code and returns the result. For example, f = @(x) x^2 creates a function handle that squares its input. Calling f(3) runs the function with x=3 and returns 9. Variables change as the handle is created and then when the function is called. This lets you use functions flexibly in your code.