Matlab Variables and Data Type Quiz
40 comprehensive questions on MATLAB's variable system and data types, covering variable creation, naming conventions, numeric types, logical values, character and string data, and inspection functions — with 16 code examples to master MATLAB's type system and variable management.
Question 1
How do you create a variable in MATLAB?
Question 2
What are the rules for variable names in MATLAB?
Question 3
What happens when you assign a new value to an existing variable in MATLAB?
>> x = 5;
>> x = 'hello';
>> class(x)
ans =
'char'Question 4
What is MATLAB's default numeric data type?
>> x = 3.14;
>> class(x)
ans =
'double'Question 5
How do you create an integer variable in MATLAB?
>> x = int32(42);
>> class(x)
ans =
'int32'Question 6
What are logical values in MATLAB?
>> x = true;
>> y = false;
>> z = 5 > 3;
>> [x y z]
ans =
1 0 1Question 7
How do you create character variables in MATLAB?
>> c = 'A';
>> class(c)
ans =
'char'Question 8
What is the difference between single quotes and double quotes in MATLAB?
>> s1 = 'hello';
>> s2 = "hello";
>> class(s1)
>> class(s2)Question 9
What does the whos command display?
>> x = 42;
>> y = 'text';
>> z = true;
>> whos
Name Size Bytes Class Attributes
x 1x1 8 double
y 1x4 8 char
z 1x1 1 logical Question 10
What does the size function return?
>> A = [1 2 3; 4 5 6];
>> size(A)
ans =
2 3Question 11
What does the class function tell you?
>> x = 3.14;
>> class(x)
ans =
'double'
>> y = int32(42);
>> class(y)
ans =
'int32'Question 12
In a data analysis project where you need to ensure variables contain numeric data before performing calculations, what inspection approach would you use to validate data types across multiple variables?
>> data1 = load('experiment1.mat');
>> data2 = load('experiment2.mat');
>>
>> % Check all variables are numeric
>> vars = whos;
>> for i = 1:length(vars)
>> if ~isnumeric(eval(vars(i).name))
>> warning('Non-numeric variable: %s', vars(i).name);
>> end
>> endQuestion 13
What happens when you assign a floating-point number to an integer type?
>> x = int32(3.7);
>> x
x =
3Question 14
How do you create a string variable in MATLAB?
>> str = "Hello World";
>> class(str)
ans =
'string'Question 15
What is the difference between char arrays and string objects?
Question 16
What does the isnumeric function check?
>> isnumeric(42)
ans =
1
>> isnumeric('text')
ans =
0Question 17
When working with large datasets, what variable naming strategy helps prevent accidental overwriting of important data?
Question 18
What is the result of logical operations on numeric values in MATLAB?
>> 5 && 0
ans =
0
>> 3.14 || 0
ans =
1Question 19
How do you check if a variable exists in the workspace?
>> exists('myVar')
ans =
0
>> myVar = 42;
>> exist('myVar')
ans =
1Question 20
What is the difference between single and double precision in MATLAB?
>> x = single(3.141592653589793);
>> y = double(3.141592653589793);
>> [x y]
ans =
3.1416 3.141592653589793Question 21
When importing data from external sources, what type checking should you perform to ensure compatibility with MATLAB's mathematical functions?
Question 22
What does the isempty function check?
>> isempty([])
ans =
1
>> isempty('')
ans =
1
>> isempty(42)
ans =
0Question 23
How do you convert between different numeric types in MATLAB?
>> x = 3.14;
>> y = int32(x);
>> z = single(y);
>> [class(x) class(y) class(z)]Question 24
What is the advantage of MATLAB's dynamic typing for rapid prototyping?
Question 25
When debugging a script with unexpected results, what sequence of inspection commands would you use to understand variable states?
>> % Script had issues, inspect variables
>> whos % See all variables and types
>> x % Display specific variable value
>> size(x) % Check dimensions
>> class(x) % Confirm data type
>> isnumeric(x) % Verify numeric typeQuestion 26
What happens when you try to access a variable that doesn't exist?
>> nonexistent_var
Unrecognized function or variable 'nonexistent_var'.Question 27
How do you create complex numbers in MATLAB?
>> z1 = 3 + 4i;
>> z2 = complex(2, 5);
>> z1 * z2
ans =
-14.0000 + 23.0000iQuestion 28
What is the purpose of the clear command in relation to data types?
>> x = 42; y = 'text';
>> whos
>> clear x
>> whos % x is gone
>> clear % clears allQuestion 29
In a collaborative MATLAB project, what naming convention helps avoid variable conflicts between team members?
Question 30
What does the islogical function check?
>> islogical(true)
ans =
1
>> islogical(42)
ans =
0Question 31
When saving variables to MAT-files for later use, what type information is preserved?
>> x = int32(42);
>> y = single(3.14);
>> save('mydata.mat', 'x', 'y');
>> clear;
>> load('mydata.mat');
>> whosQuestion 32
What is the difference between == and isequal for comparing variables?
>> a = [1 2 3];
>> b = [1 2 3];
>> a == b
>> isequal(a, b)Question 33
How do you check for special floating-point values in MATLAB?
>> x = 0/0;
>> isnan(x)
ans =
1
>> y = 1/0;
>> isinf(y)
ans =
1Question 34
What is the most efficient way to initialize multiple variables of different types in MATLAB?
>> [a, b, c] = deal(42, 'hello', true);
>> whosQuestion 35
In a computational script that processes user inputs of unknown type, what type checking strategy ensures robust operation?
Question 36
What does the length function return for different data types?
>> length([1 2 3 4])
ans =
4
>> length('hello')
ans =
5
>> length(42)
ans =
1Question 37
When working with very large numeric datasets, what type consideration becomes most important for memory efficiency?
Question 38
What is the result of concatenating different data types in MATLAB?
>> [42, 'text']
Error using horzcat
Dimensions of arrays being concatenated are not consistent.Question 39
How do you determine if a variable contains integer or floating-point data?
>> x = 42;
>> isinteger(x)
ans =
0
>> isfloat(x)
ans =
1Question 40
Considering MATLAB's type system as a whole, what core design principle enables its flexibility for technical computing while maintaining performance?