How To Import Python

Python is a popular programming language due to its simplicity and versatility. One of the reasons it is so powerful is that it provides access to a vast ecosystem of libraries that perform specific tasks. In this tutorial, we will discuss how to import Python libraries and use them to streamline your coding process.

Step 1: Install The Python Library

Before you can import a Python library, you will need to make sure it is installed on your system. To do this, use the Python package manager, pip. Open your command-line interface and run the following command to install the desired library, replacing “library_name” with the name of the library you want to use.

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pip install library_name

For example, to install the widely used library NumPy (Numerical Python), you would type:

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pip install numpy

Step 2: Import The Python Library

Once the library is installed, you are ready to import it and use it in your Python script. To import the library, use the import keyword followed by the library name.

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import library_name

For instance, to import the NumPy library, you would add the following line to your Python script:

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import numpy

Step 3: Use A Function From The Imported Library

Now that the library is imported, you can call any available functions. To access a function from an imported library, use the library name, followed by a dot, and the function name.

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library_name.function_name()

For example, to use NumPy’s arange() function, which creates an array of evenly spaced values within a given range:

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numpy.arange(0, 10, 2)

This would generate an array with the numbers [0, 2, 4, 6, 8].

Step 4: Use An Alias To Simplify Library Names

Typing the full library name each time you want to use a function can be cumbersome, especially when working with libraries with long names. To make it easier, you can create an alias for the library using the as keyword when importing it. This allows you to shorten the library name to something more manageable.

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import library_name as alias_name

For instance, NumPy is commonly imported using the alias “np”:

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import numpy as np

Now, when calling a function from the NumPy library, you can use the shorter alias:

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np.arange(0, 10, 2)

Step 5: Import Specific Functions From A Library

In some cases, you might only want to use one or a few functions from a library. Instead of importing the entire library, you can selectively import specific functions using the from keyword.

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from library_name import function_name

For example, importing only the arange() function from NumPy:

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from numpy import arange

Now, you can use the arange() function directly, without having to specify the library or alias name:

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arange(0, 10, 2)

Full code:

In this example, we use NumPy to generate an array of numbers using the arange() function, demonstrating the different ways to import and use functions from Python libraries.

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import numpy
 
numbers = numpy.arange(0, 10, 2)
print(numbers)
 
import numpy as np
numbers = np.arange(0, 10, 2)
print(numbers)
 
from numpy import arange
numbers = arange(0, 10, 2)
print(numbers)

Output

[0 2 4 6 8]
[0 2 4 6 8]
[0 2 4 6 8]

Conclusion

Importing and using Python libraries facilitates the development process by providing access to a wide range of pre-built functions. When working with Python libraries, remember to install them using pip, import them using either full names or aliases, and call their functions as needed. This will help streamline your code and make it more readable and efficient.