Creating a boolean array in Python is a straightforward process. A boolean array is an array that holds only two values, either True or False.

Itâ€™s a powerful data structure that has many applications. In this tutorial, we will walk through the steps of creating a boolean array in Python.

### Step 1: Import NumPy Library

The first step in creating a boolean array in Python is to import the NumPy library. NumPy is a powerful library for working with arrays. You can install it by running:

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pip install numpy |

You can then import the library using the following code:

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import numpy as np |

### Step 2: Create A Boolean Array

To create a boolean array in Python, we can use the np.array() function. This function takes a sequence of elements and converts it into an array. In this case, we will use a sequence of True and False values to create a boolean array. Here is the code:

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a = np.array([True, False, True, False])<br>print(a) |

The output will be:

**Output:**

[ True False True False]

### Step 3: Use Boolean Expression To Filter An Array

One of the main applications of a boolean array is to filter an array based on a condition. For example, you can filter all the values in an array that are greater than a certain value. Here is an example:

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b = np.array([1, 2, 3, 4, 5])<br>mask = b > 3<br>print(mask)<br>print(b[mask]) |

The output will be:

## Output:

[False False False True True]

[4 5]

In this example, we created an array b with the values 1 through 5, and then we created a boolean mask using the expression b > 3. This expression returns a boolean array that contains True values for all the elements that are greater than 3. We then used this mask to filter the original array b and printed the values that meet the condition.

## Conclusion

Creating a boolean array in Python is an important skill that can be extremely useful in many applications. In this tutorial, we walked through the steps of creating a boolean array using the NumPy library. We also demonstrated how to use a boolean array to filter an array based on a condition.

Here is the full code for creating a boolean array:

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import numpy as np<br>a = np.array([True, False, True, False])<br>print(a)<br>b = np.array([1, 2, 3, 4, 5])<br>mask = b > 3<br>print(mask)<br>print(b[mask]) |