Writing text files (writetable, fprintf) in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to write a table to a text file using writetable.

MATLAB

T = table([1; 2; 3], {'A'; 'B'; 'C'}, 'VariableNames', {'ID', 'Letter'});
writetable(T, '[1]');

Drag options to blanks, or click blank then click option'

A'output.txt'

Boutput.txt

C'output'

Doutput

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around the filename.

Omitting the file extension.

The filename must be a string enclosed in single quotes, like 'output.txt'.

2fill in blank

medium

Complete the code to open a file for writing using fopen.

MATLAB

fid = fopen('data.txt', '[1]');

Drag options to blanks, or click blank then click option'

A'rw'

B'w'

C'a'

D'r'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'r' which is read-only mode.

Using 'a' which appends instead of overwriting.

Use 'w' to open a file for writing, which creates or overwrites the file.

3fill in blank

hard

Fix the error in the fprintf statement to write a number and a string to the file.

MATLAB

fid = fopen('log.txt', 'w');
num = 10;
str = 'test';
fprintf(fid, '[1]', num, str);
fclose(fid);

Drag options to blanks, or click blank then click option'

A'%d %d\n'

B'%s %d\n'

C'%f %s\n'

D'%d %s\n'

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of %d and %s.

Using %f for integers.

Use '%d' for integer and '%s' for string in the format specifier.

4fill in blank

hard

Fill both blanks to write a table to a CSV file without row names.

MATLAB

T = table([4; 5], {'X'; 'Y'}, 'VariableNames', {'Num', 'Char'});
writetable(T, '[1]', 'WriteRowNames', [2]);

Drag options to blanks, or click blank then click option'

A'data.csv'

Btrue

Cfalse

D'data.txt'

Attempts:

3 left

💡 Hint

Common Mistakes

Using .txt extension instead of .csv.

Setting 'WriteRowNames' to true by mistake.

Use 'data.csv' as filename and false to avoid writing row names.

5fill in blank

hard

Fill all three blanks to write formatted data to a file using fprintf.

MATLAB

fid = fopen('results.txt', 'w');
values = [1.5, 2.5, 3.5];
for i = 1:length(values)
    fprintf(fid, '[1]', values(i));
end
fclose(fid);

Drag options to blanks, or click blank then click option'

AValue: %.1f\n

BValue: %d\n

CValue: %f\n

DValue: %s\n

Attempts:

3 left

💡 Hint

Common Mistakes

Using %d which is for integers.

Using %s which is for strings.

Use '%.1f' to format the number with one decimal place.