How to use try Except to throw an exception in python
Try is too useful for python automated testing students.
We need to make sure that each use case gets what we expect and gives the correct pass or fail results in the test report.
It can be well implemented through the try statement, and the result of this pass or fail can be guaranteed to be true.
I. try statement
Usually we use the following format:
Here, when xxxx1 is established, the xxxx3 statement under else is executed.
Execute the xxxx2 statement under except when xxxx1 is not established
Whether xxxx1 is true or not, statements under finally are executed to the
The above formats can be used in the judgment scenario of our use case to get the result of pass or fail.
II. Except type (the type of exception that is thrown)
1. Catch all exceptions:
Try: xxxx1except Exception as e: print (e) # print all exceptions to the screen
2. Catch exceptions of the type:
Try: xxxx1except TypeError as e: print (e) # print type exception to screen
There are many types of exceptions, some of which can write their own exception class and then call it.
Exception type:
Exception name description
The base class of all BaseException exceptions
SystemExit interpreter request exit
KeyboardInterrupt user interrupts execution (usually input ^ C)
Base class of Exception general error
The StopIteration iterator has no more values.
An exception occurred in the GeneratorExit generator (generator) to notify the exit
SystemExit Python interpreter request exit
The base class for all built-in standard exceptions in StandardError
The base class of all numerical calculation errors in ArithmeticError
FloatingPointError floating point calculation error
OverflowError numerical operation exceeds maximum limit
ZeroDivisionError divides (or modulates) zero (all data types)
AssertionError assertion statement failed
The AttributeError object does not have this property
EOFError has no built-in input, arriving at the EOF tag
Base class of EnvironmentError operating system error
IOError input / output operation failed
OSError operating system error
WindowsError system call failed
ImportError failed to import module / object
KeyboardInterrupt user interrupts execution (usually input ^ C)
Base class for LookupError invalid data query
There is no such index in the IndexError sequence (index)
This key is not in the KeyError map
MemoryError memory overflow error (not fatal for Python interpreter)
NameError does not declare / initialize objects (no properties)
UnboundLocalError accesses uninitialized local variables
ReferenceError weak reference (Weak reference) attempts to access objects that have been garbage collected
General runtime errors in RuntimeError
Methods that NotImplementedError has not yet implemented
SyntaxError Python syntax error
IndentationError indent error
TabError Tab mixed with spaces
SystemError general interpreter system error
TypeError operation that is not valid for type
ValueError passes in invalid parameters
UnicodeError Unicode related errors
Errors in UnicodeDecodeError Unicode decoding
Error in UnicodeEncodeError Unicode coding
Error in UnicodeTranslateError Unicode conversion
Base class for Warning warnings
DeprecationWarning warning about deprecated features
FutureWarning warning that the semantics of the construction will change in the future
OverflowWarning's old warning about automatically promoting to long integer (long)
PendingDeprecationWarning warning that features will be discarded
Warning of suspicious runtime behavior (runtime behavior) of RuntimeWarning
Warning of SyntaxWarning's suspicious syntax
Warnings generated by UserWarning user code
