How to Create Multiple CSV Files in Python

In this tutorial, we are going to be looking at how one can create multiple CSV files using Python. This is a particularly useful aspect when dealing with vast amounts of data that need to be separated for easy utilization and processing. The Python language provides several libraries we can leverage for this function, among them being the csv and the os library.

Step 1: Import Necessary Libraries

Import the necessary Python libraries. In this case, you’ll need to import the csv and os libraries.

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import csv
import os

Step 2: Define your data

Define the data you want to write into your CSV files. In the example below we are using a simple dictionary containing three lists of values. Each list will represent data for a separate CSV file.

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data = {'file1': ['a', 'b', 'c'], 'file2': ['d', 'e', 'f'], 'file3': ['g', 'h', 'i']}

Step 3: Write Function to Create and Write to File

Next, write a function that creates a CSV file and writes data into it. The function should take in a filename and a list of values as parameters. Make use of the built-in Python csv.writer() function to write to the file.

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def write_to_csv(filename, values):
    with open(filename, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerow(values)

Step 4: Iterate Over Data and Create Files

Finally, iterate over the data you defined earlier. For each item in the dictionary, call the function you defined, passing in the key of the dictionary item as the filename and the value as the values to write.

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for filename, values in data.items():
    write_to_csv(f'{filename}.csv', values)

Full Code

Bringing it all together, your code should look like this:

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import csv
import os
 
data = {'file1': ['a', 'b', 'c'], 'file2': ['d', 'e', 'f'], 'file3': ['g', 'h', 'i']}
 
def write_to_csv(filename, values):
    with open(filename, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerow(values)
 
for filename, values in data.items():
    write_to_csv(f'{filename}.csv', values)

With the above function, 3 CSV files named ‘file1.csv’, ‘file2.csv’, and ‘file3.csv’ would be created in the current directory. Each file will have a single row of data, containing the values associated with the corresponding filename in the dataset.

Conclusion

Today we’ve learned how to create and write multiple CSV files using Python. Being familiar with these concepts is helpful when needing to manipulate large amounts of data that require splitting or organizing for processing. We hope this tutorial has been informative for you. Feel free to refer to Python’s csv and os library documentation for more information.