File path handling in MATLAB - Mini Project: Build & Apply

File path handling

📖 Scenario: You are organizing files on your computer. You want to work with file paths to find the folder name, file name, and extension easily.

🎯 Goal: You will create a MATLAB script that extracts the folder path, file name, and file extension from a full file path string.

📋 What You'll Learn

Create a variable with a full file path string

Create variables to hold parts of the file path

Use MATLAB functions to split the file path into folder, name, and extension

Display the extracted parts clearly

💡 Why This Matters

🌍 Real World

Handling file paths is important when working with files and folders on your computer. It helps you organize, find, and manage files easily.

💼 Career

Many jobs in data analysis, programming, and IT require working with file paths to read and save files correctly.

1

Create the full file path string

Create a variable called fullPath and set it to the string 'C:\Users\Alice\Documents\report.pdf'.

MATLAB

% Create the variable fullPath with the exact file path string
% Your code here

Hint

Use single quotes for strings in MATLAB. Use double backslashes to write a single backslash in the string.

2

Prepare variables for folder, name, and extension

Create three variables called folderPath, fileName, and fileExt and set them to empty strings ''.

MATLAB

fullPath = 'C:\Users\Alice\Documents\report.pdf';
% Create empty strings for folderPath, fileName, and fileExt
% Your code here

Hint

Set each variable to two single quotes with nothing between them to make an empty string.

3

Extract folder path, file name, and extension

Use the MATLAB function fileparts with fullPath to assign the folder path to folderPath, the file name to fileName, and the extension to fileExt.

MATLAB

fullPath = 'C:\Users\Alice\Documents\report.pdf';
folderPath = '';
fileName = '';
fileExt = '';
% Use fileparts to split fullPath into folderPath, fileName, and fileExt
% Your code here

Hint

Use square brackets to capture multiple outputs from fileparts.

4

Display the extracted parts

Use disp to print the values of folderPath, fileName, and fileExt each on its own line.

MATLAB

fullPath = 'C:\Users\Alice\Documents\report.pdf';
[folderPath, fileName, fileExt] = fileparts(fullPath);
% Display folderPath, fileName, and fileExt using disp
% Your code here

Hint

Use disp(variable) to show the content of each variable.

Practice

1. What does the MATLAB function fullfile do?

easy

A. Joins folder and file names into a full file path safely

B. Splits a full file path into folder, name, and extension

C. Reads the contents of a file

D. Deletes a file from the disk

Solution

1. Step 1: Understand the purpose of fullfile

   fullfile is used to combine folder and file names into one complete path, handling different operating systems correctly.

2. Step 2: Compare with other functions

   fileparts splits paths, reading or deleting files are unrelated to fullfile.

3. Final Answer:

   Joins folder and file names into a full file path safely -> Option A

4. Quick Check:

   fullfile joins paths [OK]

Hint: Remember: fullfile combines parts into one path [OK]

Common Mistakes:

• Confusing fullfile with fileparts
• Thinking fullfile reads or deletes files
• Assuming fullfile only works on Windows

2. Which of the following is the correct syntax to split a full file path into folder, name, and extension in MATLAB?

easy

A. [folder, name, ext] = fileparts(path);

B. [folder, name, ext] = splitfile(path);

C. split(path, folder, name, ext);

D. fileparts = [folder, name, ext](path);

Solution

1. Step 1: Recall the correct function name and syntax

   The MATLAB function to split a path is fileparts, and it returns folder, name, and extension as outputs.

2. Step 2: Check the syntax format

   The correct syntax uses square brackets for multiple outputs: [folder, name, ext] = fileparts(path);

3. Final Answer:

   [folder, name, ext] = fileparts(path); -> Option A

4. Quick Check:

   fileparts splits path correctly [OK]

Hint: Use square brackets and fileparts to split paths [OK]

Common Mistakes:

• Using wrong function name like splitfile
• Incorrect output assignment syntax
• Trying to call fileparts like a variable

3. What is the output of the following MATLAB code?

fullPath = fullfile('C:', 'Users', 'Documents', 'file.txt');
[folder, name, ext] = fileparts(fullPath);
disp(folder)

medium

A. file.txt

B. C:\Users\Documents

C. C:/Users/Documents/file.txt

D. Documents

Solution

1. Step 1: Understand fullfile output

   fullfile joins parts into a full path: 'C:\Users\Documents\file.txt' (Windows style).

2. Step 2: Use fileparts to split the path

   fileparts splits into folder = 'C:\Users\Documents', name = 'file', ext = '.txt'.

3. Final Answer:

   C:\Users\Documents -> Option B

4. Quick Check:

   fileparts folder output = C:\Users\Documents [OK]

Hint: fileparts(folder) excludes file name and extension [OK]

Common Mistakes:

• Expecting file name or extension as folder output
• Confusing path separators (\ vs /)
• Thinking fullfile returns a list instead of string

4. Identify the error in this MATLAB code snippet:

path = fullfile('folder', 'subfolder', 'file.txt');
[folder, name, ext] = fileparts(path);
disp(name)

medium

A. The fullfile function cannot join more than two parts

B. The function fileparts requires three output variables, not one

C. There is no error; the code runs correctly and displays 'file'

D. Variable path is a reserved word and should not be used

Solution

1. Step 1: Check variable naming

   Although path is a common variable name, it is not reserved in MATLAB and can be used safely.

2. Step 2: Verify function usage

   fileparts can return multiple outputs, but it also works correctly with three outputs as shown. fullfile can join multiple parts, more than two.

3. Final Answer:

   There is no error; the code runs correctly and displays 'file' -> Option C

4. Quick Check:

   Code runs and shows file name [OK]

Hint: Check if code runs before assuming errors [OK]

Common Mistakes:

• Thinking path is a reserved keyword
• Believing fullfile only joins two parts
• Assuming fileparts needs different syntax

5. You want to create a MATLAB script that saves a file named data.csv inside a folder results located in the current working directory. Which code snippet correctly creates the full path to save the file, regardless of the operating system?

hard

A. savePath = ['results' filesep 'data.csv'];

B. savePath = strcat('results\', 'data.csv');

C. savePath = 'results/data.csv';

D. savePath = fullfile(pwd, 'results', 'data.csv');

Solution

1. Step 1: Understand the need for OS-independent path

   Using fullfile with pwd (current folder) ensures the path works on Windows, Mac, or Linux.

2. Step 2: Analyze each option

   savePath = ['results' filesep 'data.csv']; uses filesep but misses pwd so path is relative; savePath = 'results/data.csv'; uses forward slash which may fail on Windows; savePath = strcat('results\', 'data.csv'); uses backslash manually which is error-prone.

3. Final Answer:

   savePath = fullfile(pwd, 'results', 'data.csv'); -> Option D

4. Quick Check:

   fullfile + pwd = OS-independent full path [OK]

Hint: Use fullfile with pwd for safe full paths [OK]

Common Mistakes:

• Hardcoding slashes instead of using fullfile
• Not including current directory with pwd
• Using strcat which ignores path separators