1
date,subject,minutes
2
2026-10-07,Python,45
3
2026-10-08,英语,30
4
2026-10-08,Python,25

1
import csv
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import sys
3
from collections.abc import Iterable, Iterator
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from dataclasses import dataclass
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from datetime import date
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from pathlib import Path
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8

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@dataclass(frozen=True)
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class StudyRecord:
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    day: date
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    subject: str
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    minutes: int
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15

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def read_records(path: Path) -> Iterator[StudyRecord]:
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    with path.open("r", encoding="utf-8-sig", newline="") as file:
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        reader = csv.DictReader(file)
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        if reader.fieldnames != ["date", "subject", "minutes"]:
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            raise ValueError("表头必须是 date,subject,minutes")
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        for row in reader:
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            line_no = reader.line_num
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            if None in row:
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                raise ValueError(f"第 {line_no} 行：字段数量过多")
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            day_text = (row.get("date") or "").strip()
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            subject = (row.get("subject") or "").strip()
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            minutes_text = (row.get("minutes") or "").strip()
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            try:
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                day = date.fromisoformat(day_text)
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            except ValueError as exc:
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                raise ValueError(f"第 {line_no} 行：无效日期 {day_text!r}") from exc
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            if not subject:
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                raise ValueError(f"第 {line_no} 行：科目不能为空")
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            try:
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                minutes = int(minutes_text)
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            except ValueError as exc:
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                raise ValueError(f"第 {line_no} 行：分钟数不是整数 {minutes_text!r}") from exc
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44
            if minutes <= 0:
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                raise ValueError(f"第 {line_no} 行：分钟数必须大于 0")
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            yield StudyRecord(day, subject, minutes)
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49

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def summarize(records: Iterable[StudyRecord]) -> dict[str, int]:
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    totals: dict[str, int] = {}
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    for record in records:
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        totals[record.subject] = totals.get(record.subject, 0) + record.minutes
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    return totals
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56

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def main() -> int:
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    source = Path(__file__).with_name("study.csv")
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60
    try:
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        totals = summarize(read_records(source))
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    except (OSError, ValueError) as exc:
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        print(f"读取失败：{exc}", file=sys.stderr)
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        return 1
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    for subject, minutes in sorted(
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        totals.items(), key=lambda item: (-item[1], item[0])
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    ):
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        print(f"{subject}：{minutes} 分钟")
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    print(f"总计：{sum(totals.values())} 分钟")
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    return 0
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73

74
if __name__ == "__main__":
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    raise SystemExit(main())

1
from datetime import date
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from study import StudyRecord, summarize
3

4
records = [
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    StudyRecord(date(2026, 10, 7), "Python", 45),
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    StudyRecord(date(2026, 10, 8), "Python", 25),
7
]
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assert summarize(records) == {"Python": 70}
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assert summarize([]) == {}