Question

Write lines of code that generate each of the following array-related errors:
??? Error: Unbalanced or unexpected parenthesis or bracket.
??? Attempted to access A(-1); index must be a positive integer
or logical.
??? Error using ==> horzcat CAT arguments dimensions are not
consistent.
??? Error using ==> vertcat CAT arguments dimensions are not
consistent.
??? In an assignment A(I) = B, the number of elements in B and
I must be the same.
??? Error using ==> plus Matrix dimensions must agree.
??? Attempted to access A(4); index out of bounds because
numel(A)=3.

Answer 1

1). ??? Error: Unbalanced or unexpected parenthesis or bracket

When the number of left paranthesis and right parenthesis does not match then this error occurs.

A =[1 2 3 4];

Array indices must be positive integers or logical values.

A(1:

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

2). ??? Attempted to access A(-1); index must be a positive integer
or logical.

There are no negative indexing. So we will get error when we try to access using negative indexes

A =[1 2 3 4 5 6];

A(-1)

Array indices must be positive integers or logical values.

3). ??? Error using ==> horzcat CAT arguments dimensions are not
consistent.

When number of rows in A and B are not equal and we use horzcat() then we will get this error.

A = [1 2 3 ; 4 5 6];

B = [10 11 12; 12 13 14;14 15 16];

horzcat(A,B)

Error using horzcat
Dimensions of arrays being concatenated are not consistent.

4). ??? Error using ==> vertcat CAT arguments dimensions are not
consistent.

When number of columns in A and B are not equal and if we use vertcat() then we will get this error.

A = [1 2 3 ; 4 5 6];

B = [10 11 ; 12 13 ;14 15 ];

vertcat(A,B)

Error using vertcat
Dimensions of arrays being concatenated are not consistent.

5). ??? In an assignment A(I) = B, the number of elements in B and
I must be the same.

When we assign more than one elements to a single position then we will get this error.

In the following example we are assigning a vector B to the first position of A. SO it gives error.

A = [1 2 3 4 5 6];

B = [7 8 9 10];

A(1) = B

Unable to perform assignment because the left and right sides have a different number of elements.

6). ??? Attempted to access A(4); index out of bounds because
numel(A)=3.

When we are trying to access an index which is not present we will get this error.

A = [1 2 3];

A(4)

Index exceeds the number of array elements (3).