第五章练习答案

00-exceptions-basics

def safe_read_file(filename):
    try:
        with open(filename, 'r') as f:
            return f.read()
    except FileNotFoundError:
        return "File not found"
    except PermissionError:
        return "Permission denied"

01-raising-and-custom

class ValidationError(Exception):
    pass

def validate_email(email):
    if '@' not in email:
        raise ValidationError("Invalid email")

02-context-managers

from contextlib import contextmanager

@contextmanager
def database_connection(db_name):
    conn = connect(db_name)
    try:
        yield conn
    finally:
        conn.close()

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