Python Programming · Module 9 of 10

Files and errors

Read and write files safely and handle errors with try/except.

📖 Key ideas

open("data.txt") opens a file; mode "r" reads, "w" writes (overwrites), "a" appends.
with open(...) as f: closes the file automatically.
Errors (exceptions) stop a program unless handled.
try/except catches errors; finally always runs.
Common errors: ValueError, TypeError, FileNotFoundError, ZeroDivisionError.

💡 Real-life example: try/except is like a seat belt: you hope not to need it, but it saves you when something goes wrong.

with openOpens a file and closes it automatically

"a" modeAdds to the end of a file

try/exceptCatches errors

FileNotFoundErrorRaised when a file is missing