# How to find data in a matrix in Matlab and Octave

Use the find() function to find data in an array on Matlab and Octave

**find(condizione);**

The argument is a condition to select the elements of the array.

The find () function returns the list of elements that satisfy the selection conditions.

## Examples

**Example 1**

Create a 3x3 matrix

>> M=[1 2 3; 4 5 6; 7 8 9]

M =

1 2 3

4 5 6

7 8 9

Type **[row, col]=find(M==5)** to find the value 5 in the array

>> [row,col]=find(M==5)

This command finds the value 5 at the coordinates row = 2 and col = 2

row = 2

col = 2

The value 5 is located at the coordinates (2; 2) that is on the second row and second column of the matrix.

**Example 2**

Type **[row,col]=find(M<3)** to find values less than 3 in the matrix

>> [row,col]=find(M<3)

In this case the variables row and col are two arrays because the selection finds more than one value that satisfies the condition.

row = [1 1]

col = [1 2]

The first element is located at the coordinates row(1)=1 e col(1)=1 that is to the coordinates (1; 1) of the matrix.

The second element is located at the coordinates row(2)=1 e col(2)=2 that is to the coordinates (1; 2) of the matrix.

**Example 3**

Type **[row,col]=find(M>10)** to find values greater than 10 in the matrix

>> [row,col]=find(M>10)

The matrix has no values greater than 10.

The row and col arrays are empty.

row = [](0x1)

col = [](0x1)

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