Appending data to a CSV file is a common task in data processing. But what if the CSV file doesn’t exist yet? Here’s a step-by-step guide on how to append a dictionary to a non-existent CSV file using Python’s csv
module.
Prerequisites:
- Python installed on your machine. π How to Install Python?
- Basic knowledge of Python programming. π Download your Python cheat sheets (free)
π§βπ» Step 1: Import CSV and OS Python Libraries
import csv import os
π§βπ» Step 2: Check if the CSV File Exists
Before appending data, check if the file exists using the os.path.exists()
function. We’ll use it in the next step. π
π§βπ» Step 3: Create a Function to Append the Dictionary to the CSV File
If the file doesn’t exist, you’ll need to write the headers (dictionary keys) first. If it does exist, simply append the data.
def append_dict_to_csv(filename, data_dict): # Check if file exists file_exists = os.path.exists(filename) # Open the file in append mode with open(filename, 'a', newline='') as csvfile: writer = csv.DictWriter(csvfile, fieldnames=data_dict.keys()) # If file doesn't exist, write the headers first if not file_exists: writer.writeheader() # Write the dictionary data writer.writerow(data_dict)
π§βπ» Step 4: Use the Function
Now, you can use the function to append a dictionary to your CSV file. If the file doesn’t exist, it will be created.
data = {"Name": "John", "Age": 30, "City": "New York"} append_dict_to_csv('data.csv', data)
π§βπ» Step 5: Verify
Open the data.csv
file to verify that the dictionary has been appended correctly. If the file didn’t exist before, you should see it created in the specified directory with the dictionary data.
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