Python List to CSV

CSV or (Comma Separated Values) file is a widely used format for storing and exchanging tabular data. It is similar/equivalent to a spreadsheet or a database but simpler and more flexible. Python provides various modules and methods to deal with CSV data, such as the CSV module, to_csv() function, etc. These methods can easily write data from a list or dictionary to a CSV file.

This blog will provide a thorough guide on how to create a CSV file from a Python list by utilizing the following methods:

• Using “write()” Method
• Using the “CSV” Module
• Using the “to_csv()” Function
• Using the “savetxt()” Function

Method 1: Create CSV File From a Python List Using “write()” Method

The “open()” function is used along with the nested for loop and “file.write()” method to create a CSV from a Python list. For further understanding, consider the following code:

In the above code:

• The list is initialized, and the “open()” function is employed to open the “CSV” or comma-separated file in “w” mode.
• The nested for loop iterates over the list and writes the list element to CSV using the “write()” method.

Output

The list has been converted into a Python CSV file.

Method 2: Create a CSV File From a Python List Using the “CSV” Module

The “csv” module supports various functions to read and write CSV files. The “csv.writer()” function is used with the “writerows()” function to create a writer object and write rows of data to that object. Let’s overview the following code for further understanding:

Here in this code:

• The “CSV” module is called/imported, and the list is initialized.
• The “open()” function is utilized to open the comma-separated file named “csv” in “w” mode.
• The “writer()” function takes the file object as an argument and creates the writer object.
• Lastly, the “writerows()” function is used to write the specified list to a CSV file named “new.csv”.

Output

The CSV file has been created from the Python list.

Method 3: Create a CSV File From a Python List Using the “to_csv()” Function

The “to_csv()” function of the Pandas module is used to convert the Pandas DataFrame to a CSV file. This function is utilized to construct/create a CSV file from a Python list. For demonstration, take the following code:

In the above example:

• The “pandas” module is imported, and nested lists are initialized.
• The “pandas.DataFrame()” function creates DataFrame by accepting the initialized list.
• This DataFrame is converted into a CSV file using the “to_csv()” function.

Output

The Python list has been converted to a CSV file.

Method 4: Create CSV File From a Python List Using the “savetxt()” Function

The “savetxt()” function of the Numpy module is used to save or store an array to a text file. We can use this method to create/construct a CSV file. Here is an example code:

In the above code:

• The “Numpy” module is imported.
• The “array()” takes the list and retrieves an array object.
• The “savetxt()” takes the file name, array, and the “delimiter” parameter as an argument to create a CSV file from the list.

Note: This method can only write a list with matching data type values otherwise TypeError is raised.

Output

The CSV file has been created successfully.

Conclusion

In Python, the “write()”, “CSV”, “to_csv()”, and the “savetxt()” methods are utilized to create a CSV file from the input list. The “write()” method is used along with a for loop and open() function to write a CSV file from a Python list. The other methods, such as the “CSV” module, “to_csv()” function of the Pandas module, and “savetxt()” function of the Numpy module, can efficiently write a CSV file from the given Python list. This guide presented a complete guide on Python list to CSV using numerous examples.