Append list of dictionaries to an existing Pandas DataFrame in Python

To append a list of dictionaries to an existing Pandas DataFrame, you can use the pd.concat() method. The older append() method has been deprecated since Pandas 1.4.0.

Creating the Initial DataFrame

First, let's create a DataFrame with some initial data ?

import pandas as pd

dataFrame = pd.DataFrame({
    "Car": ['BMW', 'Audi', 'XUV', 'Lexus', 'Volkswagen'],
    "Place": ['Delhi', 'Bangalore', 'Pune', 'Chandigarh', 'Mumbai'],
    "Units": [100, 150, 50, 110, 90]
})

print("Original DataFrame:")
print(dataFrame)

Original DataFrame:
        Car       Place  Units
0       BMW       Delhi    100
1      Audi   Bangalore    150
2       XUV        Pune     50
3     Lexus  Chandigarh    110
4 Volkswagen      Mumbai     90

Creating List of Dictionaries

Now, create a list of dictionaries that we want to append ?

import pandas as pd

# List of dictionaries to append
new_data = [
    {'Car': 'Mustang', 'Place': 'Hyderabad', 'Units': 60},
    {'Car': 'Tesla', 'Place': 'Kerala', 'Units': 30},
    {'Car': 'RollsRoyce', 'Place': 'Punjab', 'Units': 70},
    {'Car': 'Bentley', 'Place': 'Gujarat', 'Units': 80}
]

print("List of dictionaries:")
print(new_data)

List of dictionaries:
[{'Car': 'Mustang', 'Place': 'Hyderabad', 'Units': 60}, {'Car': 'Tesla', 'Place': 'Kerala', 'Units': 30}, {'Car': 'RollsRoyce', 'Place': 'Punjab', 'Units': 70}, {'Car': 'Bentley', 'Place': 'Gujarat', 'Units': 80}]

Using pd.concat() Method

The recommended way to append data is using pd.concat() ?

import pandas as pd

# Original DataFrame
dataFrame = pd.DataFrame({
    "Car": ['BMW', 'Audi', 'XUV', 'Lexus', 'Volkswagen'],
    "Place": ['Delhi', 'Bangalore', 'Pune', 'Chandigarh', 'Mumbai'],
    "Units": [100, 150, 50, 110, 90]
})

print("Original DataFrame:")
print(dataFrame)

# List of dictionaries to append
new_data = [
    {'Car': 'Mustang', 'Place': 'Hyderabad', 'Units': 60},
    {'Car': 'Tesla', 'Place': 'Kerala', 'Units': 30},
    {'Car': 'RollsRoyce', 'Place': 'Punjab', 'Units': 70},
    {'Car': 'Bentley', 'Place': 'Gujarat', 'Units': 80}
]

# Convert list of dictionaries to DataFrame
new_df = pd.DataFrame(new_data)

# Append using concat
result_df = pd.concat([dataFrame, new_df], ignore_index=True)

print("\nAfter appending:")
print(result_df)

Original DataFrame:
        Car       Place  Units
0       BMW       Delhi    100
1      Audi   Bangalore    150
2       XUV        Pune     50
3     Lexus  Chandigarh    110
4 Volkswagen      Mumbai     90

After appending:
        Car       Place  Units
0       BMW       Delhi    100
1      Audi   Bangalore    150
2       XUV        Pune     50
3     Lexus  Chandigarh    110
4 Volkswagen      Mumbai     90
5   Mustang   Hyderabad     60
6     Tesla      Kerala     30
7 RollsRoyce      Punjab     70
8   Bentley     Gujarat     80

Key Parameters

The ignore_index=True parameter resets the index in the final result, creating a continuous index sequence starting from 0.

Conclusion

Use pd.concat() to append a list of dictionaries to a DataFrame by first converting the list to a DataFrame. The ignore_index=True parameter ensures proper index sequencing in the result.