File handling is an essential skill in Python programming, allowing you to read from and write to files with ease. Whether you’re logging data, reading configurations, or processing text files, understanding how to handle files can significantly enhance your applications. In this guide, we’ll explore three practical examples of file handling in Python, complete with explanations and code snippets.
In many applications, you may need to store logs or user-generated content in a text file. This example demonstrates how to create a new text file and write data to it.
## Open (or create) a file named 'output.txt' in write mode
with open('output.txt', 'w') as file:
# # Write some lines to the file
file.write('Hello, World!\n')
file.write('This is my first file handling example in Python.\n')
file.write('Enjoy coding!\n')
with statement automatically closes the file after the block of code is executed, which is a good practice to prevent file corruption or memory leaks.output.txt already exists, this code will overwrite it. Use 'a' mode for appending instead.Once you have data stored in a text file, you may need to read it for processing. This example shows how to read the contents of a file line by line.
## Open the file 'output.txt' in read mode
with open('output.txt', 'r') as file:
# # Read each line from the file
for line in file:
# # Print each line
print(line.strip()) # .strip() removes leading/trailing whitespace
strip() cleans up each line by removing unnecessary whitespace or newline characters, making the output cleaner.FileNotFoundError. You can handle this with a try-except block if needed.CSV (Comma-Separated Values) files are commonly used for data exchange. Python’s built-in csv module makes it easy to read from and write to CSV files. This example demonstrates how to read a CSV file and store the information in a list.
import csv
## Open the CSV file in read mode
with open('data.csv', 'r') as csvfile:
# # Create a CSV reader object
csvreader = csv.reader(csvfile)
# # Initialize a list to store rows
data = []
# # Loop through each row in the CSV file
for row in csvreader:
data.append(row) # Add the row to the list
## Print the data read from the CSV file
print(data)
data.csv file exists and is formatted correctly; otherwise, the reader may produce unexpected results.csv.writer to create and write CSV files in a similar way as we did with text files.In conclusion, these examples of file handling in Python should provide you with a solid foundation to manage files effectively in your projects. Happy coding!