Getting started with Python--18--exceptions and try,except statements

Python Standard Exception Summary

Assertionerror	Assertion statement (assert) failed
Attributeerror	Attempting to access an unknown object property
Eoferror	User input file End flag EOF (CTRL+D)
Floatingpointerror	Floating-point calculation error
Generatorexit	When the Generator.close () method is called
Importerror	When the import module fails
Indexerror	Index out of range of sequence
Keyerror	Find a keyword that does not exist in the dictionary
Keyboardinterrupt	User input interrupt key (CTRL + C)
Memoryerror	Memory overflow (can free memory by deleting objects)
Nameerror	Try to access a non-existent variable
Notimplementederror	Methods that have not been implemented
OSError	An exception generated by the operating system (for example, opening a file that does not exist)
Overflowerror	Numeric operation exceeds maximum limit
Referenceerror	Weak references (weak reference) attempt to access an object that has been reclaimed by the garbage collection mechanism
RuntimeError	General run-time errors
Stopiteration	There are no more values for iterators
SyntaxError	Syntax error for Python
Indentationerror	Indentation Error
Taberror	Use the tab and Space mix
Systemerror	Python Compiler system error
Systemexit	Python compiler process is closed
TypeError	Invalid operations between different types
Unboundlocalerror	Access an uninitialized local variable (subclass of Nameerror)
Unicodeerror	Unicode-related errors (subclasses of ValueError)
Unicodeencodeerror	Error in Unicode encoding (subclass of Unicodeerror)
Unicodedecodeerror	Error in Unicode decoding (subclass of Unicodeerror)
Unicodetranslateerror	Error in Unicode conversion (subclass of Unicodeerror)
ValueError	Invalid parameter passed in
Zerodivisionerror	Divide by zero

The following is a hierarchy of Python built-in exception classes:

Baseexception
+--Systemexit
+--Keyboardinterrupt
+--Generatorexit
+--Exception
+--stopiteration
+--Arithmeticerror
| +--Floatingpointerror
| +--Overflowerror
| +--Zerodivisionerror
+--Assertionerror
+--Attributeerror
+--Buffererror
+--Eoferror
+--Importerror
+--Lookuperror
| +--Indexerror
| +--Keyerror
+--Memoryerror
+--Nameerror
| +--Unboundlocalerror
+--OSError
| +--Blockingioerror
| +--Childprocesserror
| +--Connectionerror
|    | +--Brokenpipeerror
|    | +--Connectionabortederror
|    | +--Connectionrefusederror
|    | +--Connectionreseterror
| +--Fileexistserror
| +--Filenotfounderror
| +--Interruptederror
| +--Isadirectoryerror
| +--Notadirectoryerror
| +--Permissionerror
| +--Processlookuperror
| +--Timeouterror
+--Referenceerror
+--RuntimeError
| +--Notimplementederror
+--SyntaxError
| +--Indentationerror
| +--Taberror
+--Systemerror
+--TypeError
+--ValueError
| +--Unicodeerror
| +--Unicodedecodeerror
| +--Unicodeencodeerror
| +--Unicodetranslateerror
+--Warning
+--deprecationwarning
+--pendingdeprecationwarning
+--runtimewarning
+--syntaxwarning
+--userwarning
+--futurewarning
+--importwarning
+--unicodewarning
+--byteswarning
+--resourcewarning

With try:

Operation

Except Exception[as result]:

Print (' wrong ')

Give some chestnuts and usage:

Try

f = open (' Why am I a file '. txt ')

Print (F.read ())

F.close ()
Except OSError:

Print (' File Error! ') #运行一下, if there is a oserror error in front of you, the message will be output

Try

f = open (' Why am I a file '. txt ')

Print (F.read ())

F.close ()
Except OSError as Reult:

Print (' File Error! The reason is: ' +str (Result) #运行一下, if the preceding is a oserror error, here will output this message plus error information

A try statement can also connect multiple except exceptions:

Try

Sum =1+ ' 1 '

f = open (' Why am I a file '. txt ')

Print (F.read ())

F.close ()
Except OSError as Reult:

Print (' File Error! The reason is: ' +str (Result) #运行一下, if the preceding is a oserror error, here will output this message plus error information

Except TypeError as result:

Print (' wrong type ')

The Try statement plus the finally:

Try

Sum =1+ ' 1 '

f = open (' Why am I a file '. txt ')

Print (F.read ())

Except OSError as Reult:

Print (' File Error! The reason is: ' +str (Result) #运行一下, if the preceding is a oserror error, here will output this message plus error information

Finally

F.close () #finally语句是无论报不报错都要执行的语句

Getting started with Python--18--exceptions and try,except statements