0. 前言
由于 Python 直接从源代码运行程序,在 Python 测试或运行代码之前没有编译器进行代码分析,因此测试和异常处理是 Python 程序开发的中的重要组成部分,我们就通过 6 道 Python 编程题来掌握常见异常处理的方法吧!
1. 第 1 题:在单元测试中测试异常
知识点描述:使用测试用例判断异常是否被抛出。
问题描述:测试某个函数抛出的 KeyError 异常的情况,请从以下选项中选出你认为正确的选项:
A.
- import unittest
- def parse_dict(dictionary, key):
- return dictionary[key]
- class TestConversion(unittest.TestCase):
- def test_bad_key(self):
- self.assertRaises(KeyError, parse_dict, 'NULL')
复制代码 B.
- import unittest
- def parse_dict(dictionary, key):
- return dictionary[key]
- class TestConversion(unittest.TestCase):
- def test_bad_key(self):
- self.assertRaises(KeyError)
复制代码 C.
- import unittest
- def parse_dict(key):
- return key
- class TestConversion(unittest.TestCase):
- def test_bad_key(self):
- self.assertRaises(KeyError)
复制代码 D.
- import unittest
- def parse_dict(key):
- return key
- class TestConversion(unittest.TestCase):
- def test_bad_key(self):
- self.assertRaises(KeyError, parse_dict, 'NULL')
复制代码正确答案: A 2. 第 2 题:多个异常的处理知识点描述:处理一个代码片段可能抛出的多个不同异常。
问题描述:有一个可能抛出多个不同异常的代码段,如何使用简洁的代码处理所有可能的异常:
A. - from urllib import error, request
- urls = ['https://blog.csdn.net','https://www.baidu.com/aaa', 1, 'https://error.url']
- for url in urls:
- try:
- request.urlopen(url)
- except (error.URLError, AttributeError):
- urls.remove(url)
- print(urls)
复制代码B. - from urllib import error, request
- urls = ['https://blog.csdn.net','https://www.baidu.com/aaa', 1, 'https://error.url']
- for url in urls[::-1]:
- try:
- request.urlopen(url)
- except AttributeError:
- urls.remove(url)
- print(urls)
复制代码C. - from urllib import error, request
- urls = ['https://blog.csdn.net','https://www.baidu.com/aaa', 1, 'https://error.url']
- for url in urls[::-1]:
- try:
- request.urlopen(url)
- except error.URLError:
- urls.remove(url)
- print(urls)
复制代码D. - from urllib import error, request
- urls = ['https://blog.csdn.net','https://www.baidu.com/aaa', 1, 'https://error.url']
- for url in urls[::-1]:
- try:
- request.urlopen(url)
- except (error.URLError, AttributeError):
- urls.remove(url)
- print(urls)
复制代码正确答案: D 3. 第 3 题:捕获所有异常知识点描述:捕获代码中存在的所有异常。
问题描述:如何捕获代码中存在的所有异常,请从以下选项中选出你认为正确的选项:
A. - list_1 = [...]
- list_2 = [...]
- def add_list(list_1, list_2):
- for i in range(len(list_1)):
- r = list_1[i] + list_2[i+1]
- try:
- add_list(list_1, list_2)
- except Exception as error:
- print(e)
复制代码B. - list_1 = [...]
- list_2 = [...]
- def add_list(list_1, list_2):
- for i in range(len(list_1)):
- r = list_1[i] + list_2[i+1]
- try:
- add_list(list_1, list_2)
- except Exception as e:
- print(e)
复制代码C. - list_1 = [...]
- list_2 = [...]
- def add_list(list_1, list_2):
- for i in range(len(list_1)):
- r = list_1[i] + list_2[i+1]
- try:
- add_list(list_1, list_2)
- except Exception:
- print(e)
复制代码D. - list_1 = [...]
- list_2 = [...]
- def add_list(list_1, list_2):
- for i in range(len(list_1)):
- r = list_1[i] + list_2[i+1]
- try:
- add_list(list_1, list_2)
- except Exception:
- print(Exception)
复制代码正确答案: B 4. 第 4 题:创建自定义异常知识点描述:将异常包装成自定义异常。
问题描述:在构建的网络相关程序中,定义自定义异常,请从以下选项中选出你认为正确的选项:
A. - class NetworkError(Exception):
- def __init__(self, message, status):
- super.__init__(self, message, status)
- self.message = message
- self.status = status
复制代码B. - class NetworkError(Exception):
- def __init__(self, message, status):
- self.message = message
- self.status = status
复制代码C. - class NetworkError(Exception):
- def __init__(self, message, status):
- super().__init__(self, message, status)
- self.message = message
- self.status = status
复制代码D. - class NetworkError(Exception):
- def __init__(self, message, status):
- super().__init__(message, status)
- self.message = message
- self.status = status
复制代码正确答案: C 5. 第 5 题:捕获异常后抛出其他异常知识点描述:捕获一个异常后抛出另一个异常。
问题描述:捕获一个异常后抛出另一个异常,同时在异常回溯中保留两个不同异常的信息,请从以下选项中选出你认为正确的答案:
A. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except ValueError as e:
- raise RuntimeError('A error occurred') from e
复制代码B. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except KeyError as e:
- raise RuntimeError('A error occurred') from e
复制代码C. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except TypeError as e:
- raise RuntimeError('A error occurred') from e
复制代码D. - from datetime import datetime
- def hello_world(num):
- return "Hello world {}!".format(num)
- for i in range(10):
- with open('log.txt', 'wt') as f:
- print(str(datetime.today()) + '\t' + hello_world(i), file=f)
复制代码正确答案: B 6. 第 6 题:重新抛出被捕获的异常知识点描述:在 except 块中捕获异常后,重新将错误抛出。
问题描述:在一个 except 代码块中捕获一个异常,但是之后想要将其重新抛出,请从以下选项中选出你认为正确的答案:
A. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except KeyError as e:
- print(example)
- raise
复制代码B. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except KeyError as e:
- print(example)
- raise RuntimeError
复制代码C. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except ValueError as e:
- print(example)
- raise RuntimeError
复制代码D. - example = {'python': 'simple', 'c': 'fast'}
- try:
- print(example['java'])
- except ValueError as e:
- print(example)
- raise
复制代码正确答案: A 试题代码地址https://codechina.csdn.net/LOVEmy134611/python_problem
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