![ï Key Error : Python raises a KeyError whenever a
dict() object is requested (using the format a =
adict[key]) and the key is not in the dictionary.
ï Value Error: In Python, a value is the information that
is stored within a certain object. To encounter a
ValueError in Python means that is a problem with the
content of the object you tried to assign the value to.](https://image.slidesharecdn.com/lect29-exceptionhandling-241201160152-ab8b01a1/85/LECT-29-EXCEPTION-HANDLING-pptx-b-9-320.jpg)
LECT 29- EXCEPTION HANDLING.pptx b.
- 2. Errors and Exceptions ï Python Errors and Built-in Exceptions: Python (interpreter) raises exceptions when it encounters errors. ï When writing a program, we, more often than not, will encounter errors. ï Error caused by not following the proper structure (syntax) of the language is called syntax error or parsing error
- 3. ï An exception in Python is an incident that happens while executing a program that causes the regular course of the program's commands to be disrupted. ï When a Python code comes across a condition it can't handle, it raises an exception. ï An object in Python that describes an error is called an exception.
- 4. Exceptions versus Syntax Errors
- 6. ï ZeroDivisionError: ZeroDivisionError in Python indicates that the second argument used in a division (or modulo) operation was zero. ï OverflowError: OverflowError in Python indicates that an arithmetic operation has exceeded the limits of the current Python runtime. This is typically due to excessively large float values, as integer values that are too big will opt to raise memory errors instead. ï ImportError: It is raised when you try to import a module which does not exist. This may happen if you made a typing mistake in the module name or the module doesn't exist in its standard path..
- 7. ï IndexError: An IndexError exception is raised when you refer a sequence which is out of range. In the example below, the list abc contains only 3 entries, but the 4th index is being accessed, which will result an IndexError exception. ï TypeError: When two unrelated type of objects are combined, TypeErrorexception is raised. ï IndentationError: Causes due to Unexpected indent.
- 8. ï Syntax errors: These are the most basic type of error. They arise when the Python parser is unable to understand a line of code. Syntax errors are almost always fatal, i.e. there is almost never a way to successfully execute a piece of code containing syntax errors. ï Run-time error: A run-time error happens when Python understands what you are saying, but runs into trouble when following your instructions
- 9. ï Key Error : Python raises a KeyError whenever a dict() object is requested (using the format a = adict[key]) and the key is not in the dictionary. ï Value Error: In Python, a value is the information that is stored within a certain object. To encounter a ValueError in Python means that is a problem with the content of the object you tried to assign the value to.
- 10. ï Python has many built-in exceptions:
- 11. ï Python uses try and except keywords to handle exceptions. Both keywords are followed by indented blocks
- 12. ï The things we need to observe are: 1. You should be able to understand the mistakes; the error might be done by user, DB connection or server. 2. Whenever there is an error execution should not stop. Ex: Banking Transaction 3. The aim is execution should not stop even though an error occurs
- 20. ï A try statement can have more than one except clause, to specify handlers for different exceptions. ï Note that at most one handler will be executed.