How to Append Pandas DataFrame to Existing CSV File

You can use the pandas’ library in Python to append data to an existing table. Appending data to an existing table is a way to add new rows of data without modifying or deleting the existing data. This is helpful if you wish to update or add new data to a database while maintaining a historical record of the old data. append(): The append() method in pandas is used to add rows to a DataFrame, and return a new DataFrame with the newly added rows. The original DataFrame remains unchanged. The new DataFrame can be assigned to a variable, which can then be used for further processing or analysis. 

• pd.concat(): pd.concat() is a function in the pandas library that is used to concatenate or join multiple DataFrames along a particular axis (axis=0 for rows and axis=1 for columns). 

pd.concat() is similar to the append() method, but it can be used to concatenate DataFrames along either the rows or columns axis, and it can also take a list of DataFrames as input, whereas append() can only take one DataFrame at a time and concatenate along the rows axis. 

For better knowledge of appending data in existing table using Pandas, you may have a look at the code below.

Fig : Preview of the output that you will get on running this code from your IDE.

Code

In this solution we're using Pandas library.

Instructions

Follow the steps carefully to get the output easily.

1. Install pandas on your IDE(Any of your favorite IDE).
2. Copy the snippet using the 'copy' and paste it in your IDE.
3. Add required dependencies and import them in Python file.
4. Run the file to generate the output.

I hope you found this useful. I have added the link to dependent libraries, version information in the following sections.

I found this code snippet by searching for 'how to append data in existing table using pandas' in kandi. You can try any such use case!

Environment Tested

I tested this solution in the following versions. Be mindful of changes when working with other versions.

1. The solution is created in PyCharm 2021.3.
2. The solution is tested on Python 3.9.7.
3. Pandas version-v1.5.2.

Using this solution, we are able to append data in existing table using pandas with simple steps. This process also facilities an easy way to use, hassle-free method to create a hands-on working version of code which would help us to append data in existing table using pandas.

Dependent Library

You can also search for any dependent libraries on kandi like 'pandas'.

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