Python exception handling
Python provides two very important functions to handle exceptions and errors that occur during the execution of Python programs. You can use this function to debug python programs.
- Exception handling: The Python tutorial on this site will introduce it in detail.
- Assertions: The Python tutorial on this site will introduce them in detail.
python standard exception
| exception name | describe |
|---|---|
| BaseException | Base class for all exceptions |
| SystemExit | interpreter request to exit |
| KeyboardInterrupt | User interrupts execution (usually by typing ^C) |
| Exception | base class for general errors |
| StopIteration | iterator has no more values |
| GeneratorExit | Generator (generator) exception to notify exit |
| StandardError | Base class for all built-in standard exceptions |
| ArithmeticError | Base class for all numerical computation errors |
| FloatingPointError | floating point calculation error |
| OverflowError | Numerical operation exceeds maximum limit |
| ZeroDivisionError | divide (or modulo) zero (all data types) |
| AssertionError | Assertion statement failed |
| AttributeError | Object does not have this property |
| EOFError | No built-in input, reaching the EOF marker |
| EnvironmentError | Base class for operating system errors |
| IOError | I/O operation failed |
| OSError | operating system error |
| WindowsError | system call failed |
| ImportError | Failed to import module/object |
| LookupError | Base class for invalid data queries |
| IndexError | There is no such index in the sequence (index) |
| KeyError | There is no such key in the map |
| MemoryError | Out of memory error (not fatal to the Python interpreter) |
| NameError | undeclared/initialized object (no properties) |
| UnboundLocalError | access uninitialized local variable |
| ReferenceError | Weak reference attempts to access objects that have been garbage collected |
| RuntimeError | General runtime errors |
| NotImplementedError | Method not yet implemented |
| SyntaxError | Python syntax error |
| IndentationError | Indentation error |
| TabError | Mixing Tabs and Spaces |
| SystemError | General interpreter system errors |
| TypeError | Invalid operation on type |
| ValueError | Invalid parameter passed in |
| UnicodeError | Unicode related errors |
| UnicodeDecodeError | Error in Unicode decoding |
| UnicodeEncodeError | Error in Unicode encoding |
| UnicodeTranslateError | Error during Unicode conversion |
| Warning | base class for warnings |
| DeprecationWarning | Warning about deprecated features |
| FutureWarning | Warning about future semantic changes of constructs |
| OverflowWarning | Old warning about auto-promotion to long |
| PendingDeprecationWarning | Warning that features will be deprecated |
| RuntimeWarning | Suspicious runtime behavior warning |
| SyntaxWarning | Suspicious syntax warning |
| UserWarning | Warnings generated by user code |
What is an exception?
An exception is an event that occurs during program execution and affects the normal execution of the program.
Typically, an exception occurs when Python cannot handle a program normally.
exceptions are Python objects representing an error.
When an exception occurs in the Python script, we need to catch it, otherwise the program will terminate execution.
try: <语句> #运行代码 except <名字> as e: <语句> #如果引发了'标准'异常，获得附加的数据e except Exception as e: <语句> #如果引发了所有异常，获得附加的数据e else: <语句> #如果没有异常发生 finally: <语句> #都要执行