Reading and Writing Files in Python (GCSE Guide)

June 19, 2026

File handling means reading data from, and writing data to, files stored on a computer. It is a required part of the GCSE Computer Science programming content, and it often appears in the exam. This guide covers the essentials with examples.

Writing to a file

Open a file in write mode ("w") and use write():

file = open("scores.txt", "w")
file.write("Alice,10\n")
file.write("Bob,8\n")
file.close()

Write mode creates the file if it does not exist, and overwrites it if it does. Always close() the file when you are done.

Reading from a file

file = open("scores.txt", "r")
contents = file.read()
print(contents)
file.close()

Reading line by line

file = open("scores.txt", "r")
for line in file:
  print(line.strip())
file.close()

strip() removes the invisible newline character at the end of each line.

Appending to a file

Append mode ("a") adds to the end of a file without deleting what is already there:

file = open("scores.txt", "a")
file.write("Carol,9\n")
file.close()

The three file modes to remember

• "r" — read (the default)
• "w" — write (overwrites the file)
• "a" — append (adds to the end)

File handling is hard to practise on a locked-down school computer — but our free online Python IDE runs real Python that supports reading and writing files safely in your browser, so you can try every example above.