Python Exceptions Reference

Quick reference to some of the exceptions (error codes) of Python.

DB Exceptions / error codes
Exception Means what
DatabaseError Used for errors in the database. Must subclass Error.
DataError Subclass of DatabaseError that refers to errors in the data.
Error Base class for errors. Must subclass StandardError.
IntegrityError Subclass of DatabaseError for situations that would damage the relational integrity, such as uniqueness constraints or foreign keys.
InterfaceError Used for errors in the database module, not the database itself. Must subclass Error.
InternalError Subclass of DatabaseError that refers to errors internal to the database module, such as a cursor no longer being active.
NotSupportedError Subclass of DatabaseError that refers to trying to call unsupported functionality.
OperationalError Subclass of DatabaseError that refers to errors such as the loss of a connection to the database. These errors are generally outside of the control of the Python script.
ProgrammingError Subclass of DatabaseError that refers to errors such as a bad table name and other errors in the script.
Warning Used for non-fatal issues. Must subclass StandardError.
General exceptions / error codes
Exception Means what
ArithmeticError Base class for all errors that occur for numeric calculation.
AssertionError Raised in case of failure of the Assert statement.
AttributeError Raised in case of failure of attribute reference or assignment.
EnvironmentError Base class for all exceptions that occur outside the Python environment.
EOFError Raised when there is no input from either the raw_input() or input() function and the end of file is reached.
Exception Base class for all exceptions
FloatingPointError Raised when a floating point calculation fails.
ImportError Raised when an import statement fails.
IndentationError Raised when indentation is not specified properly.
IndexError Raised when an index is not found in a sequence.
IOError Raised when an input/ output operation fails, such as the print statement or the open() function when trying to open a file that does not exist.
KeyboardInterrupt Raised when the user interrupts program execution, usually by pressing Ctrl+c.
KeyError Raised when the specified key is not found in the dictionary.
LookupError Base class for all lookup errors.
NameError Raised when an identifier is not found in the local or global namespace.
NotImplementedError Raised when an abstract method that needs to be implemented in an inherited class is not actually implemented.
OSError Raised when a system function returns a system-related error, including I/O failures such as “file not found” or “disk full” (not for illegal argument types or other incidental errors).
OverflowError Raised when a calculation exceeds maximum limit for a numeric type.
RuntimeError Raised when a generated error does not fall into any other category.
StandardError Base class for all built-in exceptions except StopIteration and SystemExit.
StopIteration Raised when the next() method of an iterator does not point to any object.
SyntaxError Raised when there is an error in Python syntax.
SystemError Raised when the interpreter finds an internal problem. When this error is encountered the Python interpreter does not exit.
SystemExit Raised when Python interpreter is quit by using the sys.exit() function. If not handled in the code this causes the interpreter to exit.
TypeError Raised when an operation or function is attempted that is invalid for the specified data type.
UnboundLocalError Raised when trying to access a local variable in a function or method but no value has been assigned to it.
ValueError Raised when the built-in function for a data type has the valid type of arguments, but the arguments have invalid values specified.
ZeroDivisionError Raised when division or modulo by zero takes place for all numeric types.