PythonFile Modes

File Modes in Python

File mode determines how a file is opened in Python: For reading For writing For appending For binary access And more…

Choosing the correct mode is critical for safe and correct file handling.

File Modes Overview

ModeDescription
'r'Read-only (default). File must exist.
'w'Write-only. Creates new file or overwrites existing.
'a'Append-only. Creates new file or appends to existing.
'r+'Read + write. File must exist.
'w+'Write + read. Overwrites existing or creates new file.
'a+'Append + read. Creates new or appends.
'b'Binary mode (e.g., 'rb', 'wb')
'x'Exclusive creation — fails if file exists.

Example 1: 'r' — Read Mode

file_mode_r.py
with open("example.txt", "r") as file:
    print(file.read())

Notes:

  • Opens file for reading
  • File must exist, otherwise error: FileNotFoundError

Example 2: 'w' — Write Mode

file_mode_w.py
with open("newfile.txt", "w") as file:
    file.write("This will create a new file or overwrite existing.")

Notes:

  • Creates newfile.txt if not present
  • Overwrites content if file exists

Example 3: 'a' — Append Mode

file_mode_a.py
with open("newfile.txt", "a") as file:
    file.write("\nAppending another line.")

Notes:

  • Adds content to end of file
  • Does not overwrite

Example 4: 'r+' — Read and Write (existing file)

file_mode_rplus.py
with open("example.txt", "r+") as file:
    content = file.read()
    print("Before:", content)
    file.seek(0)
    file.write("Updated first line.\n")

Notes:

  • File must exist
  • Allows both reading and writing

Example 5: 'w+' — Write and Read (overwrite)

file_mode_wplus.py
with open("newfile2.txt", "w+") as file:
    file.write("New content here.\n")
    file.seek(0)
    print("After write:", file.read())

Notes:

  • Overwrites or creates file
  • Can read and write

Example 6: 'a+' — Append and Read

file_mode_aplus.py
with open("newfile2.txt", "a+") as file:
    file.write("Appending again!\n")
    file.seek(0)
    print("File content:\n", file.read())

Notes:

  • Appends content
  • Can also read

Example 7: 'x' — Exclusive Creation

file_mode_x.py
with open("unique.txt", "x") as file:
    file.write("File created uniquely.")

Notes:

  • Fails if file already exists: FileExistsError

Binary Modes: 'rb', 'wb'

Used for non-text files: Images Audio/video Executables

Example 8: Reading Binary File

file_mode_rb.py
with open("image.png", "rb") as file:
    data = file.read(10)
    print(data)

Notes:

  • 'rb' — read binary
  • Returns bytes, not strings

Example 9: Writing Binary File

file_mode_wb.py
with open("copy_image.png", "wb") as file:
    with open("image.png", "rb") as original:
        file.write(original.read())

Notes:

  • 'wb' — write binary
  • Can copy image/audio files

Summary

File mode controls how files are opened:

  • Read ('r')
  • Write ('w')
  • Append ('a')
  • Combined read/write ('r+', 'w+', 'a+')
  • Exclusive create ('x')
  • Binary ('rb', 'wb')

Always choose the mode appropriate for your use case Using with open() ensures safe file handling

Next, we will learn about Using with Statement — how it makes file handling safer and more readable.

Reading and Writing FilesUsing `with` Statement