How to Convert Pandas DataFrame Column to List

1. Use the tolist() Method to Convert a Dataframe Column to a List
2. Use the list() Function to Convert a Dataframe Column to a List
3. Use the .values Property to Convert a Dataframe Column to a List
4. Use List Comprehension to Convert a Dataframe Column to a List
5. Conclusion

When working with Pandas DataFrames in Python, you might often need to convert a column of your DataFrame into a Python list. This process can be crucial for various data manipulation and analysis tasks. Fortunately, Pandas provides several methods to achieve this, making it easy to extract the data you need in list form.

In this article, we’ll explore different methods to convert a Pandas DataFrame column into a Python list. We’ll demonstrate these methods using a sample DataFrame that contains information about names, dates of birth (DOB), and salaries.

import pandas as pd

data = {
    "Name": ["James", "Michelina", "Marc", "Bob", "Halena"],
    "DOB": ["1/1/2014", "2/1/2014", "3/1/2014", "4/1/2014", "4/1/2014"],
    "Salary": ["1000", "12000", "36000", "15000", "12000"],
}

df = pd.DataFrame(data, columns=["Name", "DOB", "Salary"])

We’ll explore four different methods to perform this conversion: using the tolist() method, the list() function, the .values property, and list comprehension. Each method has its advantages, so let’s dive in.

Use the tolist() Method to Convert a Dataframe Column to a List

A column in the Pandas dataframe is a Pandas Series. So if we need to convert a column to a list, we can use tolist() method in the Series. tolist() converts the Series of pandas data-frame to a list.

In the code below, df['DOB'] returns the Series, or the column, with the name as DOB from the DataFrame.

The tolist() method converts the Series to a list.

import pandas as pd

df = pd.DataFrame(
    [
        ["James", "1/1/2014", "1000"],
        ["Michelina", "2/1/2014", "12000"],
        ["Marc", "3/1/2014", "36000"],
        ["Bob", "4/1/2014", "15000"],
        ["Halena", "4/1/2014", "12000"],
    ],
    columns=["Name", "DOB", "Salary"],
)

print("Pandas DataFrame:\n\n", df, "\n")

list_of_single_column = df["DOB"].tolist()

print(
    "the list of a single column from the dataframe\n",
    list_of_single_column,
    "\n",
    type(list_of_single_column),
)

Output:

Pandas DataFrame:

         Name       DOB Salary
0      James  1/1/2014   1000
1  Michelina  2/1/2014  12000
2       Marc  3/1/2014  36000
3        Bob  4/1/2014  15000
4     Halena  4/1/2014  12000 

the list of a single column from the dataframe
 ['1/1/2014', '2/1/2014', '3/1/2014', '4/1/2014', '4/1/2014'] 
 <class 'list'>

Use the list() Function to Convert a Dataframe Column to a List

We can also use the list() function to convert a DataFrame column to a list, by passing the DataFrame to the list() function.

We will use the same data as above to demonstrate this approach.

import pandas as pd

df = pd.DataFrame(
    [
        ["James", "1/1/2014", "1000"],
        ["Michelina", "2/1/2014", "12000"],
        ["Marc", "3/1/2014", "36000"],
        ["Bob", "4/1/2014", "15000"],
        ["Halena", "4/1/2014", "12000"],
    ],
    columns=["Name", "DOB", "Salary"],
)

print("Pandas DataFrame:\n\n", df, "\n")

list_of_single_column = list(df["DOB"])

print(
    "the list of a single column from the dataframe\n",
    list_of_single_column,
    "\n",
    type(list_of_single_column),
)

Output:

Pandas DataFrame:

         Name       DOB Salary
0      James  1/1/2014   1000
1  Michelina  2/1/2014  12000
2       Marc  3/1/2014  36000
3        Bob  4/1/2014  15000
4     Halena  4/1/2014  12000 

the list of a single column from the dataframe
 ['1/1/2014', '2/1/2014', '3/1/2014', '4/1/2014', '4/1/2014'] 
 <class 'list'>

Use the .values Property to Convert a Dataframe Column to a List

Another way to achieve this is by using the .values property.

Let’s go through the steps of converting the ‘Salary’ column of this DataFrame into a Python list using the .values property.

The .values property of a Pandas Series returns a NumPy array representation of the data. To convert it into a Python list, you can use the .tolist() method. Here’s how you do it:

salary_list = df["Salary"].values.tolist()

Here’s the complete code:

import pandas as pd

data = {
    "Name": ["James", "Michelina", "Marc", "Bob", "Halena"],
    "DOB": ["1/1/2014", "2/1/2014", "3/1/2014", "4/1/2014", "4/1/2014"],
    "Salary": ["1000", "12000", "36000", "15000", "12000"],
}

df = pd.DataFrame(data, columns=["Name", "DOB", "Salary"])

# Convert the 'Salary' column to a list using .values
salary_list = df["Salary"].values.tolist()

print(salary_list)

Output:

['1000', '12000', '36000', '15000', '12000']

After executing this code, the Salary column from the DataFrame will be converted into a Python list, which is stored in the salary_list variable.

Use List Comprehension to Convert a Dataframe Column to a List

List comprehension is a concise and efficient way to create lists in Python. To convert a column of a Pandas DataFrame into a Python list using list comprehension, you can follow the below code.

# Using list comprehension to convert the 'Salary' column to a list
salary_list = [salary for salary in df["Salary"]]

Here’s the complete code:

import pandas as pd

data = {
    "Name": ["James", "Michelina", "Marc", "Bob", "Halena"],
    "DOB": ["1/1/2014", "2/1/2014", "3/1/2014", "4/1/2014", "4/1/2014"],
    "Salary": [1000, 12000, 36000, 15000, 12000],
}

df = pd.DataFrame(data, columns=["Name", "DOB", "Salary"])

# Using list comprehension to convert the 'Salary' column to a list
salary_list = [salary for salary in df["Salary"]]

print(salary_list)

Output:

[1000, 12000, 36000, 15000, 12000]

Conclusion

In this article, we explored four different methods to convert a Pandas DataFrame column into a Python list: using the tolist() method, the list() function, the .values property, and list comprehension. Each method has its advantages and can be chosen based on your specific use case and coding style.

Whether you prefer the simplicity of the tolist() method, the standard Pythonic approach of the list() function, the efficiency of the .values property, or the readability of list comprehension, Pandas offers multiple options to help you seamlessly convert your DataFrame columns into Python lists.