'''
時間：2018/11/03
目錄: 
　　一: 正常執行
        1 正常
        2 else
　　二: 發生錯誤
        1 異常
        2 異常
    三: BaseException
    四: 多層錯誤 - 多層捕獲
    五: 記錄錯誤
    六: 丟擲錯誤
'''

一: 正常執行
　　1 正常

# coding:utf-8


try:
    print("try...")
    r = 10 / 2                    # 正常執行
    print
 
("result:", r)
except ZeroDivisionError as e:
    print("except:", e)
finally:
    print("finally...")
print("END")

try...
result: 5.0
finally...
END

　　2 else

# coding:utf-8


try:
    print('try...')
    r = 10 / int('2')
    print('result:', r)
except ValueError as e:
    print('ValueError:
 
', e)
except ZeroDivisionError as e:
    print('ZeroDivisionError:', e)
else:
    print('no error!')      # 沒有錯誤 - 執行else
finally:
    print('finally...')
print('END')

try...
result: 5.0
no error!
finally...
END

二: 發生錯誤
　　1 異常

# coding:utf-8


try:
    print("try...")
    r = 10 / 0                    #
 
 發生異常
    print("result:", r)
except ZeroDivisionError as e:    # 除法錯誤
    print("except:", e)
finally:
    print("finally...")
print("END")

try...
except: division by zero
finally...
END

　　2 異常

# coding:utf-8


try:
    print('try...')
    r = 10 / int('a')
    print('result:', r)
except ValueError as e:               # 變數錯誤
    print('ValueError:', e)
except ZeroDivisionError as e:        # 除法錯誤
    print('ZeroDivisionError:', e)
finally:
    print('finally...')
print('END')

try...
ValueError: invalid literal for int() with base 10: 'a'
finally...
END

三: BaseException

# coding:utf-8

def foo():
    return 10 / 0

try:
    foo()
except BaseException as e:            # 所有錯誤
    print('BaseException', e)
except ZeroDivisionError as e:        # 除法錯誤
    print('ZeroDivisionError:', e)
except ValueError as e:               # 變數錯誤
    print('ValueError', e)
except UnicodeError as e:             # 編碼錯誤
    print('UnicodeError', e)

BaseException division by zero

1 :  BaseException接管 - 除法錯誤

# coding:utf-8

def foo():
    return 10 / int('a')

try:
    foo()
except BaseException as e:            # 所有錯誤
    print('BaseException', e)
except ZeroDivisionError as e:        # 除法錯誤
    print('ZeroDivisionError:', e)
except ValueError as e:               # 變數錯誤
    print('ValueError', e)
except UnicodeError as e:             # 編碼錯誤
    print('UnicodeError', e)

BaseException invalid literal for int() with base 10: 'a'

1 :  BaseException接管 - 變數錯誤

1 :  python3.6.7 錯誤型別的繼承關係。

四: 多層錯誤 - 多層捕獲

# coding:utf-8


def foo(s):
    return 10 / int(s)

def bar(s):
    return foo(s) * 2

def main():
    try:
        print("try...")
        bar('0')
        print("try...end")
    except Exception as e:
        print('Error:', e)
    finally:
        print('finally...')

main()

1 :  try...except... 跨越多層呼叫。

# coding:utf-8

def foo(s):
    return 10 / int(s)

def bar(s):
    return foo(s) * 2

def main():
    bar('0')

main()

Traceback (most recent call last):
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 12, in <module>
    main()
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 10, in main
    bar('0')
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 7, in bar
    return foo(s) * 2
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 4, in foo
    return 10 / int(s)
ZeroDivisionError: division by zero

1 :  如果錯誤沒被程式捕獲，最終會被python直譯器捕獲

五: 記錄錯誤

# coding:utf-8


import logging

def foo(s):
    return 10 / int(s)

def bar(s):
    return foo(s) * 2

def main():
    try:
        print("try...")
        bar('0')
        print("try...end")
    except Exception as e:
        print("except...")
        logging.exception(e)
    finally:
        print("finally...")

main()
print('END')

try...
except...
finally...
END
ERROR:root:division by zero
Traceback (most recent call last):
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 14, in main
    bar('0')
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 9, in bar
    return foo(s) * 2
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 6, in foo
    return 10 / int(s)
ZeroDivisionError: division by zero

1 :  logging模組可以讓程式繼續執行，並記錄錯誤資訊，把錯誤記錄到日誌檔案裡。

六: 丟擲錯誤

# coding:utf-8

def foo(s):
    n = int(s)
    if n==0:
        raise ValueError('invalid value: %s' % s)
    return 10 / n

def bar():
    try:
        foo('0')
    except ValueError as e:
        print('ValueError!')
        raise   # 捕獲錯誤 - 暫不處理

bar()

ValueError!
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 16, in <module>
    bar()
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 11, in bar
    foo('0')
  File "D:/ProgramTools/PyCharm 5.0.4/PycharmProject/python_get/study001/study001.py", line 6, in foo
    raise ValueError('invalid value: %s' % s)
ValueError: invalid value: 0