Pandas – Get Column Values as a Numpy Array

In this tutorial, we will know how to get the column values of a Pandas Dataframe as a Numpy Array.
Later, we will understand the same with the help of a few examples.

We can get the column values of a dataframe as a numpy array –

• by the to_numpy() method
• by the to_records() method

1. Using the to_numpy() method :

You can use the pandas series to_numpy() function to create a numpy array from the values of a pandas dataframe column.
We can directly apply the to_numpy() method to the column as shown in the syntax below.

Syntax: dataFrameName['ColumnName'].to_numpy()

2. Using the to_records() method.:

You can use the pandas dataframe to_records() method to first convert the dataframe to a numpy array (it returns a numpy recarray object, which you can think of as a numpy array that allows field access via attributes) and then access the specific column values as a 1d array.
The following is the syntax –
Syntax:

  arrayname = dataFrameName.to_records()
  arrayname["ColumnName"]`

Here as you can see, firstly we convert the entire dataframe into records, and then access the column that we want from that set of records (the two-dimensional numpy array).

📚 Data Science Programs By Skill Level

Introductory ⭐

• Harvard University Data Science: Learn R Basics for Data Science
• Standford University Data Science: Introduction to Machine Learning
• UC Davis Data Science: Learn SQL Basics for Data Science
• IBM Data Science: Professional Certificate in Data Science
• IBM Data Analysis: Professional Certificate in Data Analytics
• Google Data Analysis: Professional Certificate in Data Analytics
• IBM Data Science: Professional Certificate in Python Data Science
• IBM Data Engineering Fundamentals: Python Basics for Data Science

Intermediate ⭐⭐⭐

• Harvard University Learning Python for Data Science: Introduction to Data Science with Python
• Harvard University Computer Science Courses: Using Python for Research
• IBM Python Data Science: Visualizing Data with Python
• DeepLearning.AI Data Science and Machine Learning: Deep Learning Specialization

Advanced ⭐⭐⭐⭐⭐

• UC San Diego Data Science: Python for Data Science
• UC San Diego Data Science: Probability and Statistics in Data Science using Python
• Google Data Analysis: Professional Certificate in Advanced Data Analytics
• MIT Statistics and Data Science: Machine Learning with Python - from Linear Models to Deep Learning
• MIT Statistics and Data Science: MicroMasters® Program in Statistics and Data Science

🔎 Find Data Science Programs 👨‍💻 111,889 already enrolled

Disclaimer: Data Science Parichay is reader supported. When you purchase a course through a link on this site, we may earn a small commission at no additional cost to you. Earned commissions help support this website and its team of writers.

Examples

We will now look at a few examples for a better understanding.

But before that, we will create a pandas dataframe that we will be using throughout this tutorial using the following command:

import pandas as pd

# employee data
data = {
    "Name": ["Jim", "Dwight", "Angela", "Tobi"],
    "Age": [26, 28, 27, 32],
    "Department": ["Sales", "Sales", "Accounting", "HR"]
}

# create pandas dataframe
df = pd.DataFrame(data)
# displays dataframe
df

Output:

Example 1: Using the to_numpy() function

Let’s get the values in the “Name” column as an array.

# get column values as numpy array
df['Name'].to_numpy()

Output:

array(['Jim', 'Dwight', 'Angela', 'Tobi'], dtype=object)

Example 2: Using the to_records() function

# convert dataframe to a recarray
arr = df.to_records() 
# get column values as numpy array
arr['Name'] 

Output:

array(['Jim', 'Dwight', 'Angela', 'Tobi'], dtype=object)

Summary

In this tutorial, we looked at how to get column values as an array in a Pandas dataframe. The following are the methods covered –

• Use the pandas series to_numpy() method to get the values of a dataframe column as a numpy array.
• Alternatively, you can use the numpy to_records() function to create a numpy recarray object and then get the column values as a 1d array from it.

You might also be interested in –

• Get Pandas Dataframe Row as a Numpy Array
• Create Pandas DataFrame from a Numpy Array
• Convert Pandas Series to a List
• Pandas DataFrame to a List in Python
• Get Column Names as List in Pandas DataFrame