Cheat sheet · Class 12 · CBSE · Science Computer Science
File Handling in Python cheat sheet
The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.
CBSE Class 12 · Computer Science
Cheat sheet
Chapter 4File Handling in Python
Open → read/write → close (or use with, which closes for you).
1. Modes
| Mode | Meaning |
|---|---|
| r / rb | read (file must exist) |
| w / wb | write (creates or overwrites) |
| a / ab | append |
| r+ / w+ / a+ | read and write |
2. Text Files
- read(n), readline(), readlines().
- write(str), writelines(list).
- with open('f.txt') as f: …
- tell() gives position; seek(offset, from) moves it.
3. Binary Files (pickle)
- pickle.dump(obj, f) — serialise.
- pickle.load(f) — deserialise; EOFError at the end.
4. CSV Files
- csv.writer(f).writerow(row) / writerows(rows).
- csv.reader(f) gives rows as lists.
- Open with newline='' when writing.
5. Key Points
- Text files store characters; binary files store bytes.
- Absolute vs relative paths.
- flush() writes the buffer.
- w mode erases existing content.
Remember: Modes | read/write methods | pickle | csv
File Handling in Python: questions and notes
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