File handling can fail because a file is absent, unreadable or malformed. Use a context manager for resource handling and catch exceptions you can address meaningfully.
Before you begin
Use a local Python environment and a small file or script. Read the error output carefully and keep sample records fictional.
Work through the idea
Begin with a tiny input whose answer you can calculate by hand. Write the expected result, implement the operation and compare the actual result. Add an empty or invalid input and state its handling explicitly. Keep input parsing separate from the main calculation where practical.
- Select encoding deliberately
- Separate parsing from file access
- Preserve useful error information
Practice task
Read a fictional transactions file and report malformed rows using line numbers.
Check your result
Show a successful file, a missing file and one malformed row without losing valid records silently.
A mistake to avoid
Do not catch every error and return an empty result that looks like success.
Keep a review note
Save the inputs or scenario, your reasoning and the result you checked. Explain one assumption and one case that needs more work. Revise the exercise after feedback and distinguish what you demonstrated from what remains untested.
Official reference for further study
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