Python exceptions All In One

合集 - Python Script(95)

1.Python List Comprehensions All In One2023-08-022.Python 3 List Type errors All In One2023-07-313.Python Files All In One2023-07-28

4.Python exceptions All In One2023-07-28

5.Python decorator method and decorator property All In One2023-07-276.Python data hiding All In One 2023-07-267.Python Magic Methods & Operator Overloading All In One2023-07-198.How to fix the for...in loop errors in Python All In One2023-06-039.How to check function arguments type in Python All In One2023-06-0210.Python rpi_ws281x library All In One2023-06-0211.Python function argument All In One2023-06-0212.How to use variable in Python String All In One2023-06-0113.How to change the default Python2 to Python3 on Linux All In One2023-05-2514.Python & PEP All In One2023-05-1915.How to use pip3 install the latest version package All In One2023-05-1716.Python for loop with index All In One2023-05-1317.Python try...catch All In One2023-05-1118.Python OOP & Class private method All In One2023-05-1119.Python range function All In One2023-05-1120.pip3 & python3 -m pip All In One2023-05-0721.Python 3 alias All In One2023-04-3022.Python Ternary Operator All In One2023-04-2823.The principle of uploading files with command line tools All In One2023-04-2824.Python __init__() method & __init__.py file All In One2023-04-2725.Python relative import local package module file All In One2023-04-2726.Python check whether a list includes some value All In One2023-04-2727. Python timezone package All In One2023-04-1328.Python script get date and time All In One2023-04-1229.如何把一个 Python 项目包发布到 PyPI 上指南教程 All In One2023-04-0130.Python 3 vs Python 2 All In One2023-03-3031.Python 脚本接收命令行参数的多种方式 All In One2023-03-3032.Python 数据类型转换 All In One2023-03-3033.Python errors All In One2023-03-2934.Python 元组解构 All In One2023-03-2835.Python custom modify the __add__ method All In One2022-08-2136.Python 3 function & *args & **kwargs All In One2022-08-2037.Python list methods All In One2022-08-1938.Python 字符串插值 All In One2022-08-1739.Pycharm 如何自定义新建的 Python 文件的注释模版 All in One2022-08-1740.Python & PEP 8 & Style Guide All In One2022-08-1741.小甲鱼 All In One2022-08-1242.PyScript All In One2022-07-2443.QRcode ORC All In One2022-04-0944.Python 3 Data Types All In One2021-05-2945.free Python ebook & videos2021-03-1546.Python API Frameworks All In One2021-03-1347.Python Read JSON File2021-02-1948.2020～2021 职业规划书2021-01-1349.Python Web Framework All In One2021-01-1050.Python errors All In One2021-01-0951.如何使用 Python 编写后端 API 接口2021-01-0952.Python Coding Interview All In One2020-09-0253.Jupyter All In One2020-09-0254.How to use PyPI to publish a Python package All In One2020-08-1855.Python3 & Decorators with arguments & @Decorators with arguments bug2020-08-1356.Python Lambda & Functional Programming2020-08-1357.Python & file operation mode2020-08-1058.Python Turtle2020-08-1059.Python 2 to Python 3 convert2020-08-0660.Spyder & Kite2020-08-0661..pyc & Python2020-08-0562.Python Learning Paths2020-08-0563.Python Web Frameworks2020-08-0564.PEP 8 & Style Guide2020-08-0565.Python Crawler All In One2020-08-0466.Python Quiz & Python Exercise2020-08-0467.Anaconda2020-08-0468.Python module all in one2020-08-0469.PIP & Python packages management All In One2020-08-0470.Versatile Python 3.x2020-08-0371.Python Tutorials2020-07-2872.Flask2020-05-2573.selenium & python2020-01-0374.如何抓取电商的数据 & Python2019-04-1675.Python & dict & switch...case All In One2019-01-3076.Spyder & Python All In One2019-01-3077.How to install python3 on macOS All In One2019-01-3078.NLP & AI2019-01-3079.macOS & Python & Redis All In One2018-10-1780.Python & Spider2018-06-2481.How to run multiple Python versions on Windows?2018-05-1782.MySQL & Python2018-05-1783.Python file 操作 open 官方的文档2016-09-2384.Python关键字查询2016-09-2285.常见算法：python 一个简单的方法来实现Fibonacci序列只用迭代器，没有任何复杂的递归数据结构！2016-09-2186.如何在pycharm中切换python版本(2/3) 的图解教程2016-09-2087.修复 PyCharm 使用中文字符 Python 报错的完美解决方案 All In One2016-09-1988.how to updating Node.js and npm2016-09-1889.PEP 8 -- Style Guide for Python Code All In One2016-09-0190.如何在 Python 中使用 UTF-8 编码 All In One2016-08-0791.sphinx 文档生成器 （基于 python ）2016-06-0792.使用 ReStructuredText + Sphinx + Python 开发wiki ebooks!2015-12-2893.如何在Eclipse正确安装配置PyDev插件的官方教程，以及error 问题的解决方法：2015-11-3094.在线的代码托管平台 coding.net ===中国扩展版github2015-11-2195.python ( pycharm EDU)2015-10-25

收起

Python exceptions All In One

Different exceptions are raised for different reasons.

Common exceptions:

• ImportError: an import fails;
• IndexError: a list is indexed with an out-of-range number;
• NameError: an unknown variable is used;
• SyntaxError: the code can't be parsed properly;
• TypeError: a function is called on a value of an inappropriate type;
• ValueError: a function is called on a value of the correct type, but with an inappropriate value.

Python has several other built-in exceptions, such as ZeroDivisionError and OSError.
Third-party libraries also often define their own exceptions.

single except

#!/usr/bin/env python3
# coding: utf8

__author__ = 'xgqfrms'
__editor__ = 'vscode'
__version__ = '1.0.1'
__github__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One'
__git__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One.git'
__copyright__ = """
  Copyright (c) 2012-2050, xgqfrms; mailto:xgqfrms@xgqfrms.xyz
"""

"""

/**
 *
 * @author xgqfrms
 * @license MIT
 * @copyright xgqfrms
 * @created 2020-01-01
 * @updated 2023-06-01
 *
 * @description
 * @augments
 * @example
 * @link
 *
 */



try:
  num1 = 7
  num2 = 0
  num3 = 2
  print (num1 / num3)
  print("✅ Done calculation")
  print (num1 / num2)
except ZeroDivisionError:
  print("❌ An error occurred, due to zero division")


"""
$ py3 ./exception-handling-try-except.py

3.5
✅ Done calculation
❌ An error occurred, due to zero division

"""

multi except

#!/usr/bin/env python3
# coding: utf8

__author__ = 'xgqfrms'
__editor__ = 'vscode'
__version__ = '1.0.1'
__github__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One'
__git__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One.git'
__copyright__ = """
  Copyright (c) 2012-2050, xgqfrms; mailto:xgqfrms@xgqfrms.xyz
"""

"""

/**
 *
 * @author xgqfrms
 * @license MIT
 * @copyright xgqfrms
 * @created 2020-01-01
 * @updated 2023-06-01
 *
 * @description
 * @augments
 * @example
 * @link
 *
 */



try:
  variable = 10
  print(variable + "hello")
  print(variable / 2)
except ZeroDivisionError:
  print("❌ Divided by zero")
except (ValueError, TypeError):
  print("❌ ValueError or TypeError occurred")

"""
$ py3 ./exception-handling-try-multi-except.py

❌ ValueError or TypeError occurred

"""

finally

try:
  print("Hello World")
  print(1 / 0)
except ZeroDivisionError:
  print("❌ Divided by zero")
finally:
  print("👻 This code will run no matter what")

"""

$ py3 ./exception-handling-try-except-finally.py

Hello World
❌ Divided by zero
👻 This code will run no matter what

"""

else

try:
   print(1)
except ZeroDivisionError:
   print("❌ ZeroDivisionError")
else:
   print("✅")

try:
   print(1/0)
except ZeroDivisionError:
   print("❌❌ ZeroDivisionError")
else:
   print("✅✅")


"""
$ py3 ./exception-handling-try-except-else.py

1
✅
❌❌ ZeroDivisionError
"""

raise

# You can throw (or `raise`) exceptions when some condition occurs.
# You need to specify the `type` of the exception raised.

try:
  num = 102
  if num > 100:
    # 自定 throw error 类型
    raise ValueError
except ValueError:
  print("❌ ValueError")

# 没有处理 raise ❌
num = 102
if num > 100:
  # 自定 throw error 类型
  raise ValueError

"""
$ py3 ./exception-handling-raise.py

❌ ValueError
Traceback (most recent call last):
  File "/Users/xgqfrms-mm/Documents/github/Python-3.x-All-In-One/src/./exception-handling-raise.py", line 16, in <module>
    raise ValueError
ValueError

"""

python get exception message

Python 3

"""
You are making a program to post tweets. Each tweet must not exceed 42 characters.

Complete the program to raise an exception, in case the length of the tweet is more than 42 characters.

You can use the len() function to calculate the length of the string.

"""

tweet = input()

try:
  #your code goes here
  if(len(tweet) > 42):
    raise ValueError("tweet 超出 42 字符的最大长度限制 ❌")
    # raise SyntaxError("tweet 超出 42 字符的最大长度限制 ❌")
except Exception as err:
  print("❌ Error =", err)
  print("❌❌ Error args =", err.args)
  print("❌❌❌ Error args[0] =", err.args[0])
# except Exception, err:
  # print("❌ Error msg", err.msg)
  # print("❌❌ Error message", err.message)
else:
  print("✅ Posted")

"""

$ py3 ./exception-handling-say-something.py

###########################################
❌ Error = tweet 超出 42 字符的最大长度限制 ❌
❌❌ Error args = ('tweet 超出 42 字符的最大长度限制 ❌',)
❌❌❌ Error args[0] = tweet 超出 42 字符的最大长度限制 ❌


$ py3 ./exception-handling-say-something.py

xgqfrms
✅ Posted

"""


"""

class SyntaxError(Exception):
    msg: str
    lineno: int | None
    offset: int | None
    text: str | None
    filename: str | None
    if sys.version_info >= (3, 10):
        end_lineno: int | None
        end_offset: int | None

class SystemError(Exception): ...
class TypeError(Exception): ...
class ValueError(Exception): ...
class FloatingPointError(ArithmeticError): ...
class OverflowError(ArithmeticError): ...
class ZeroDivisionError(ArithmeticError): ...
class ModuleNotFoundError(ImportError): ...
class IndexError(LookupError): ...
class KeyError(LookupError): ...
class UnboundLocalError(NameError): ...


"""

Python 2

# old ❌
try:
  # ...
except Exception, e:
  # ...

# new ✅
try:
  # ...
except Exception as e:
  # ...

https://docs.python.org/zh-cn/3/library/exceptions.html

https://docs.python.org/3/tutorial/errors.html

⚠️ 注意事项:

对于 Python 3 的 Exception，与 Python 2 的 Exception 相比，有两个需要注意的地方：

1. 在 Python 3 Exception 的 except 子句中，不支持使用逗号 ',' 分隔 Exception 和 e，所以需要采用 as 关键词进行替换；
2. 与 Python 2 Exception 类相比，Python 3 Exception 类没有 message 成员变量。
   针对这个问题，可以使用 err.args 方法获取得到相关的异常信息。
   针对这个问题，可以使用 sys.exc_info() 方法获取得到相关的异常信息。

https://www.cnblogs.com/xgqfrms/p/17589042.html#5197603

demos

#!/usr/bin/env python3
# coding: utf8

__author__ = 'xgqfrms'
__editor__ = 'vscode'
__version__ = '1.0.1'
__github__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One'
__git__ = 'https://github.com/xgqfrms/Python-3.x-All-In-One.git'
__copyright__ = """
  Copyright (c) 2012-2050, xgqfrms; mailto:xgqfrms@xgqfrms.xyz
"""

"""

/**
 *
 * @author xgqfrms
 * @license MIT
 * @copyright xgqfrms
 * @created 2020-01-01
 * @updated 2023-06-01
 *
 * @description
 * @augments
 * @example
 * @link
 *
 */



# setter/getter

class Pizza:
  def __init__(self, toppings):
    self.toppings = toppings
    self._pineapple_allowed = False

  @property
  def pineapple_allowed(self):
    return self._pineapple_allowed

  # property setter
  @pineapple_allowed.setter
  def pineapple_allowed(self, value):
    if value:
      password = input("Enter the password: ")
      if password == "123":
        self._pineapple_allowed = value
      else:
        raise ValueError("Alert! Intruder!")
  @pineapple_allowed.getter
  def pineapple_allowed(self):
    return "✅" + str(self._pineapple_allowed)

try:
  pizza = Pizza(["cheese", "tomato"])
  print(pizza.toppings)
  print(pizza._pineapple_allowed)
  print("\npizza.pineapple_allowed =", pizza.pineapple_allowed)
  pizza.pineapple_allowed = True
  print(pizza.pineapple_allowed)
except ValueError:
  print("ValueError")
finally:
  print("finished")

"""

$ py3 ./class-property-setter-getter.py

['cheese', 'tomato']
False

pizza.pineapple_allowed = ✅False
Enter the password: 123
✅True

"""

refs

---

---

©xgqfrms 2012-2021

www.cnblogs.com/xgqfrms 发布文章使用：只允许注册用户才可以访问！

原创文章，版权所有©️xgqfrms, 禁止转载 🈲️，侵权必究⚠️！

---