eq, ==

Create two vectors containing both real and imaginary numbers, then compare the vectors for equality.

A = [1+i 3 2 4+i];
B = [1 3+i 2 4+i];
A == B

ans = 1×4 logical array

   0   0   1   1

The eq function tests both real and imaginary parts for equality, and returns logical 1 (true) only where both parts are equal.

Create a character vector.

M = 'magenta';

Test for the presence of a specific character using ==.

M == 'e'

ans = 1×7 logical array

   0   0   0   1   0   0   0

The value of logical 1 (true) indicates the presence of the character 'e'.

Create a categorical array with two values: 'heads' and 'tails'.

A = categorical({'heads' 'heads' 'tails'; 'tails' 'heads' 'tails'})

A = 2×3 categorical
     heads      heads      tails 
     tails      heads      tails 

Find all values in the 'heads' category.

A == 'heads'

ans = 2×3 logical array

   1   1   0
   0   1   0

A value of logical 1 (true) indicates a value in the category.

Compare the rows of A for equality.

A(1,:) == A(2,:)

ans = 1×3 logical array

   0   1   1

A value of logical 1 (true) indicates where the rows have equal category values.

Many numbers expressed in decimal text cannot be represented exactly as binary floating numbers. This leads to small differences in results that the == operator reflects.

Perform a few subtraction operations on numbers expressed in decimal and store the result in C.

C = 0.5-0.4-0.1

C = 
-2.7756e-17

With exact decimal arithmetic, C should be equal to exactly 0. Its small value is due to the nature of binary floating-point arithmetic.

Compare C to 0 for equality.

C == 0

ans = logical
   0

Compare floating-point numbers using a tolerance, tol, instead of using ==.

tol = eps(0.5);
abs(C-0) < tol

ans = logical
   1

The two numbers, C and 0, are closer to one another than two consecutive floating-point numbers near 0.5. In many situations, C may act like 0.

Compare the elements of two datetime arrays.

Create two datetime arrays in different time zones.

t1 = [2014,04,14,9,0,0;2014,04,14,10,0,0];
A = datetime(t1,'TimeZone','America/Los_Angeles');
A.Format = 'd-MMM-y HH:mm:ss Z'

A = 2×1 datetime
   14-Apr-2014 09:00:00 -0700
   14-Apr-2014 10:00:00 -0700

t2 = [2014,04,14,12,0,0;2014,04,14,12,30,0];
B = datetime(t2,'TimeZone','America/New_York');
B.Format = 'd-MMM-y HH:mm:ss Z'

B = 2×1 datetime
   14-Apr-2014 12:00:00 -0400
   14-Apr-2014 12:30:00 -0400

Check where elements in A and B are equal.

A==B

ans = 2×1 logical array

   1
   0

Since R2023a

Create two tables and compare them. The row names (if present in both) and variable names must be the same, but do not need to be in the same orders. Rows and variables of the output are in the same orders as the first input.

A = table([1;2],[3;4],VariableNames=["V1","V2"],RowNames=["R1","R2"])

A=2×2 table
          V1    V2
          __    __

    R1    1     3 
    R2    2     4 

B = table([4;2],[3;1],VariableNames=["V2","V1"],RowNames=["R2","R1"])

B=2×2 table
          V2    V1
          __    __

    R2    4     3 
    R1    2     1 

A == B

ans=2×2 table
           V1       V2  
          _____    _____

    R1    true     false
    R2    false    true