Practical 4: Program to Append Data to an Already Existing File.
Problem Statement
Write a Python program to append new data to an already existing file without deleting its previous content.
Solution Code
# Program to append data to an existing file
# Open the file in append mode
file = open("output.txt", "a")
# Data to be appended
new_data = ["This is an appended line.\n",
"Appending another line to the file.\n"]
# Append data using writelines()
file.writelines(new_data)
# Close the file
file.close()
print("Data appended to output.txt successfully.")
Expected Outcome
If output.txt already contains:
Hello, this is line 1.
This is line 2.
Writing to a file using writelines(). This is an appended line.
Appending another line to the file.
A success message is printed:
Data appended to output.txt successfully.
Process finished with exit code 0
Explanation
Below is the explanation of F.E. PPS Unit 4 Practical 4 solution where we have written Python program to append new data to an already existing file without deleting its previous content.
- Opening the File in Append Mode
- open(“output.txt”, “a”) opens the file in append mode (a), ensuring that new content is added instead of overwriting existing data.
- Appending Data Using writelines()
- A list of new lines is created and written to the file.
- Since writelines() does not automatically add new lines, \n is included in each string.
- Closing the File
- file.close() ensures the file is saved properly.
- Displaying a Success Message
- Confirms that data has been appended successfully.
Key Concepts Learned
- Append Mode (a) in File Handling
- Ensures new content is added without removing previous content.
- Using writelines() for Adding Multiple Lines
- Efficient way to append a list of lines to a file.
- File Closing Importance
- Prevents file corruption and ensures data is written properly.
