Excel file reading and writing in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read data from an Excel file named 'data.xlsx'.

MATLAB

data = readtable('[1]');

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

Adata.csv

Bdata.xlsm

Cdata.txt

Ddata.xlsx

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong file extension like .csv or .txt.

Forgetting to put the filename in quotes.

The readtable function reads data from an Excel file. The filename must be a string with the correct Excel file extension, here 'data.xlsx'.

2fill in blank

medium

Complete the code to write the table 'T' to an Excel file named 'output.xlsx'.

MATLAB

writetable(T, '[1]');

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

Ainput.xlsx

Boutput.xlsx

Cresults.csv

Ddata.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Using a filename with the wrong extension like .csv or .txt.

Not putting the filename in quotes.

The writetable function saves the table T to an Excel file. The filename must be a string with the desired Excel file name, here 'output.xlsx'.

3fill in blank

hard

Fix the error in the code to read only the sheet named 'Sheet2' from 'data.xlsx'.

MATLAB

data = readtable('data.xlsx', 'Sheet', [1]);

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

A'sheet2'

B2

C'Sheet2'

DSheet2

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of a string for the sheet name.

Not quoting the sheet name.

Using wrong case like 'sheet2' instead of 'Sheet2'.

The sheet name must be a string with quotes and exact case, so use 'Sheet2'. Using a number reads the sheet by index instead of by name, and using an unquoted name causes a syntax error.

4fill in blank

hard

Fill both blanks to read data from 'data.xlsx' sheet 'Sales' and write it to 'summary.xlsx'.

MATLAB

data = readtable('[1]', 'Sheet', '[2]');
writetable(data, 'summary.xlsx');

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

Adata.xlsx

Bsummary.xlsx

CSales

DSheet1

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the filenames or sheet names.

Using wrong sheet name like 'Sheet1' instead of 'Sales'.

To read from 'data.xlsx' sheet 'Sales', use those exact strings. Writing is done to 'summary.xlsx' already in code.

5fill in blank

hard

Fill all three blanks to read 'Sheet1' from 'input.xlsx', select rows where 'Age' > 30, and write to 'filtered.xlsx'.

MATLAB

data = readtable('[1]', 'Sheet', '[2]');
filtered = data(data.[3] > 30, :);
writetable(filtered, 'filtered.xlsx');

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

Ainput.xlsx

BSheet1

CAge

DAgeGroup

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong sheet name or filename.

Using a wrong column name for filtering.

Not using the correct syntax for filtering rows.

Read from 'input.xlsx' sheet 'Sheet1'. Filter rows where the column 'Age' is greater than 30. Then write filtered data to 'filtered.xlsx'.

Practice

1. Which MATLAB function is used to read data from an Excel file into a table?

easy

A. csvread

B. xlswrite

C. readtable

D. load

Solution

1. Step 1: Identify the function for reading Excel files

   MATLAB provides readtable to import Excel data as a table.

2. Step 2: Differentiate from other functions

   xlswrite writes data, csvread reads CSV files, and load loads MAT files.

3. Final Answer:

   readtable -> Option C

4. Quick Check:

   Excel read function = readtable [OK]

Hint: Use readtable to import Excel data as tables quickly [OK]

Common Mistakes:

• Confusing readtable with xlswrite
• Using csvread for Excel files
• Trying to use load for Excel data

2. Which of the following is the correct syntax to write a table T to an Excel file named data.xlsx?

easy

A. readtable('data.xlsx', T)

B. write(T, 'data.xlsx')

C. xlsread('data.xlsx', T)

D. writetable(T, 'data.xlsx')

Solution

1. Step 1: Identify the correct function for writing tables

   The function writetable writes tables to Excel files.

2. Step 2: Check the syntax

   The syntax is writetable(T, 'filename.xlsx'). Other options are either reading functions or incorrect.

3. Final Answer:

   writetable(T, 'data.xlsx') -> Option D

4. Quick Check:

   Write table syntax = writetable(T, filename) [OK]

Hint: Use writetable with table and filename to save Excel files [OK]

Common Mistakes:

• Using write instead of writetable
• Confusing xlsread with writing
• Passing table as second argument to readtable

3. What will be the output of the following MATLAB code?

T = readtable('sales.xlsx', 'Sheet', 'Q1', 'Range', 'A1:C5');
disp(height(T));

medium

A. 4

B. 5

C. 3

D. 6

Solution

1. Step 1: Understand the readtable range and header

   The range 'A1:C5' includes 5 rows, but the first row is usually the header.

2. Step 2: Calculate the number of data rows

   Since the first row is header, the data rows are 5 - 1 = 4.

3. Final Answer:

   4 -> Option A

4. Quick Check:

   Rows read minus header = 4 [OK]

Hint: Remember first row is header, so data rows = total rows - 1 [OK]

Common Mistakes:

• Counting header row as data
• Confusing range size with number of rows
• Assuming no header row present

4. Identify the error in this MATLAB code snippet that tries to write a table T to the second sheet of results.xlsx:

writetable(T, 'results.xlsx', 'Sheet', 2, 'Range', 'B2');

medium

A. The 'Sheet' parameter must be a string, not a number

B. The 'Range' parameter cannot be used with writetable

C. The filename must include full path

D. writetable cannot write to Excel files

Solution

1. Step 1: Check the 'Sheet' parameter type

   In writetable, the 'Sheet' argument should be a string with sheet name, not a numeric index.

2. Step 2: Validate other parameters

   'Range' is valid, filename can be relative, and writetable supports Excel files.

3. Final Answer:

   The 'Sheet' parameter must be a string, not a number -> Option A

4. Quick Check:

   Sheet name must be string in writetable [OK]

Hint: Use sheet names as strings, not numbers, in writetable [OK]

Common Mistakes:

• Passing sheet number instead of name
• Thinking Range is invalid for writetable
• Assuming filename needs full path always

5. You want to read only the numeric data from the range B2:D10 in sheet Data of metrics.xlsx into MATLAB as a table. Which code snippet correctly does this and then writes only the first 5 rows back to a new Excel file subset.xlsx?

hard

A. T = readmatrix('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10');
writetable(T(1:5,:), 'subset.xlsx');

B. T = readtable('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10');
writetable(T(1:5,:), 'subset.xlsx');

C. T = readtable('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10');
writetable(T(1:5));

D. T = readmatrix('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10');
writetable(T, 'subset.xlsx');

Solution

1. Step 1: Read numeric data as a table

   Use readtable with 'Sheet' and 'Range' to get data as a table.

2. Step 2: Write first 5 rows to new Excel file

   Use writetable with T(1:5,:) to write first 5 rows correctly.

3. Final Answer:

   T = readtable('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10'); writetable(T(1:5,:), 'subset.xlsx'); -> Option B

4. Quick Check:

   readtable + subset rows + writetable = T = readtable('metrics.xlsx', 'Sheet', 'Data', 'Range', 'B2:D10'); writetable(T(1:5,:), 'subset.xlsx'); [OK]

Hint: Use readtable with range, then slice rows before writetable [OK]

Common Mistakes:

• Using readmatrix but then writetable on matrix
• Omitting filename in writetable
• Not slicing rows correctly before writing