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# isequal

Determine array equality

## Description

example

tf = isequal(A,B) returns logical 1 (true) if A and B are the same size and their contents are of equal value; otherwise, it returns logical 0 (false). The test compares both real and imaginary parts of numeric arrays. isequal ignores the data type of the values in determining whether they are equal. For cell arrays, categorical arrays, tables, or structures, the function returns logical 1 (true) only when all elements and properties are numerically equal. Undefined categorical elements or NaN (not a number) values are considered to be unequal to other elements, as well as themselves.

example

tf = isequal(A1,A2,...,An) returns logical 1 (true) if all the inputs are numerically equal.

## Examples

expand all

### Compare Two Numeric Matrices

Create two numeric matrices and compare them for equality.

```A = zeros(3,3)+1e-20;
B = zeros(3,3);
tf = isequal(A,B)
```
```tf =

0```

The function returns logical 0 (false) because the matrices differ by a very small amount and are not exactly equal.

### Compare Two Structures

Create two structures and specify the fields in a different order.

```A = struct('field1',0.005,'field2',2500);
B = struct('field2',2500,'field1',0.005);
```

Compare the structures for equality.

```tf = isequaln(A,B)
```
```tf =

1```

Even though the ordering of the fields in each structure is different, isequal treats them as the same because the values are equal.

### Comparing Numeric Values with Special Nonnumeric Values

Compare the logical value true to the double integer 1.

```isequal(true,1)
```
```ans =

1```

Notice that isequal does not consider data type when it tests for equality.

Similarly, compare 'A' to the ASCII-equivalent integer, 65.

```isequal('A',65)
```
```ans =

1```

The result is logical 1 (true) since double('A') equals 65.

### Compare Vectors Containing NaN Values

Create three vectors containing NaN values.

```A1 = [1 NaN NaN];
A2 = [1 NaN NaN];
A3 = [1 NaN NaN];
```

Compare the vectors for equality.

```tf = isequal(A1,A2,A3)
```
```tf =

0
```

The result is logical 0 (false) because isequal does not treat NaN values as equal to each other.

## Input Arguments

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### A,B — Inputs to be comparednumeric arrays | categorical arrays | cell arrays | tables | structures | ...

Inputs to be compared, specified as numeric arrays, categorical arrays, cell arrays, tables, or structures. Also, you can specify the inputs as logical arrays, character arrays, or objects. The numeric types of A and B do not have to match.

You can compare a categorical array to a cell array of strings of the same size, or a single categorical element to a single string.

If inputs A and B are both

• Structures -- Fields need not be in the same order as long as the contents are equal.

• Ordinal categorical arrays -- Must have the same sets of categories, including their order.

• Categorical arrays that are not ordinal -- Can have different sets of categories, and isequal compares the category names of each pair of elements.

• Objects of different classes -- isequal returns logical 0 (false). This applies even when the objects have the same properties and their values match.

### A1,A2,...,An — Series of inputs to be comparednumeric arrays | categorical arrays | cell arrays | tables | structures | ...

Series of inputs to be compared, specified as numeric arrays, categorical arrays, cell arrays, tables, or structures. Also, you can specify the inputs as logical arrays, character arrays, or objects. The numeric types of the inputs do not have to match.

You can compare categorical arrays to cell arrays of strings of the same size, or single categorical elements to single strings.

If the inputs are all

• Structures -- Fields need not be in the same order as long as the contents are equal.

• Ordinal categorical arrays -- Must have the same sets of categories, including their order.

• Categorical arrays that are not ordinal -- Can have different sets of categories, and isequal compares the category names of each pair of elements.

• Objects of different classes -- isequal returns logical 0 (false). This applies even when the objects have the same properties and their values match.