Parse Error Recovery

Robustly parse a whitespace-separated string into a list of valid integers, skipping invalid tokens.

parsing exceptions error-handling strings

Implement a function `parse_numbers(text: str) -> list` that takes a string `text` and parses it into a list of integers. The input is a sequence of tokens separated by whitespace (spaces, tabs, newlines). Each token can be either a valid integer (optionally signed, e.g., `123`, `-45`, `+7`) or an invalid token (any other non-empty token). The parser must recover from errors: when encountering an invalid token, skip it and continue with the next token, so that valid numbers are still collected. Your function should not raise exceptions; it should return the list of successfully parsed integers in the order they appear. Use exception handling (try/except) to detect invalid tokens. Empty tokens (e.g., from consecutive spaces) should be ignored. Function signature: `def parse_numbers(text: str) -> list:` For example, `parse_numbers("1 abc 2 -3")` returns `[1, 2, -3]`. The input string may be empty, in which case return `[]`.

Constraints

- `text` is a string of length up to 100,000.
- Tokens are separated by whitespace (spaces, tabs, newlines).
- A valid integer is an optionally signed sequence of decimal digits, with no spaces inside.
- Invalid tokens include things like `12.5`, `0x1F`, `1.0`, or non-numeric strings.
- The resulting list may be empty.
- Time complexity should be O(n) where n is the length of the string.

Example

>>> parse_numbers("1 abc 2 -3")
[1, 2, -3]
>>> parse_numbers("10 20 30")
[10, 20, 30]
>>> parse_numbers("")
[]
>>> parse_numbers("  12.5  three  -4  five  ")
[-4]

10 points ~15 min

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Hints

Split the input by whitespace using `text.split()` to get tokens.

For each token, try `int(token)` inside a try block.

Catch `ValueError` to skip invalid tokens.

Return the collected list of valid integers.

Test Results

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