Mastering CSV Files in Python: A Comprehensive Guide
Getting Started with csv.writer()
When it comes to working with CSV files in Python, the csv module is an essential tool. If you’re new to using csv, our tutorial on Python CSV: Read and Write CSV files is a great place to start. Let’s dive into the basics of using csv.writer() to write data into CSV files.
Example 1: Writing to a CSV File
Suppose we want to create a CSV file with the following entries:
Using csv.writer(), we can achieve this with just a few lines of code. When we run the program, an innovators.csv file is created in the current working directory with the given entries.
Writing Multiple Rows with writerows()
What if we need to write the contents of a 2-dimensional list to a CSV file? The writerows() function makes it easy. The output of the program is the same as in Example 1.
Customizing Your CSV Files
CSV Files with Custom Delimiters
By default, a comma is used as a delimiter in a CSV file. But what if we need to use a different delimiter, such as | or \t? We can pass an additional delimiter parameter to the csv.writer() function to achieve this.
Example 3: Writing a CSV File with a Pipe Delimiter
CSV Files with Quotes
Some CSV files have quotes around each or some of the entries. To add quotes to our entries, we can use the quoting parameter. Let’s take an example of how quoting can be used around non-numeric values with ; as delimiters.
Example 4: Writing a CSV File with Quotes
CSV Files with Custom Quoting Characters
We can also write CSV files with custom quoting characters. For that, we’ll use the quotechar parameter. Let’s take an example of writing a quotes.csv file with * as the quoting character.
Example 5: Writing a CSV File with a Custom Quoting Character
Dialects in the CSV Module
When working with multiple CSV files, using dialects can simplify our code and make it more modular. A dialect groups together specific formatting patterns like delimiter, skipinitialspace, quoting, and escapechar into a single dialect name.
Example 6: Writing a CSV File Using a Dialect
Write CSV Files with csv.DictWriter()
The csv.DictWriter() class can be used to write to a CSV file from a Python dictionary. Let’s take an example of how to use csv.DictWriter() to write a players.csv file.
Example 7: Python csv.DictWriter()
CSV Files with lineterminator
A lineterminator is a string used to terminate lines produced by writer objects. We can change its value by passing any string as a lineterminator parameter.
doublequote & escapechar in the CSV Module
The csv module uses double quotes to escape the quote character present in the entries by default. We can also use the escapechar parameter to escape the delimiter if quoting is set to csv.QUOTE_NONE.
Example 8: Using escapechar in csv writer
With these examples and explanations, you should now have a solid understanding of how to work with CSV files in Python using the csv module. Happy coding!