Error in Python can be of two types i.e. Syntax errors and Exceptions. Errors are the problems in a program due to which the program will stop the execution. On the other hand, exceptions are raised when some internal events occur which changes the normal flow of the program.
Note: For more information, refer Errors and Exceptions in Python
Some of the common Exception Errors are :
- IOError : if the file can’t be opened
- KeyboardInterrupt : when an unrequired key is pressed by the user
- ValueError : when built-in function receives a wrong argument
- EOFError : if End-Of-File is hit without reading any data
- ImportError : if it is unable to find the module
Try Except in Python
Try and Except statement is used to handle these errors within our code in Python. The try block is used to check some code for errors i.e the code inside the try block will execute when there is no error in the program. Whereas the code inside the except block will execute whenever the program encounters some error in the preceding try block.
try: # Some Code except: # Executed if error in the # try block
How try() works?
- First, try clause is executed i.e. the code between try and except clause.
- If there is no exception, then only try clause will run, except clause is finished.
- If any exception occured, try clause will be skipped and except clause will run.
- If any exception occurs, but the except clause within the code doesn’t handle it, it is passed on to the outer try statements. If the exception left unhandled, then the execution stops.
- A try statement can have more than one except clause
Code 1: No exception, so try clause will run.
('Yeah ! Your answer is :', 1)
Code 1: There is an exception so only except clause will run.
Sorry ! You are dividing by zero
In python, you can also use the else clause on the try-except block which must be present after all the except clauses. The code enters the else block only if the try clause does not raise an exception.
try: # Some Code except: # Executed if error in the # try block else: # execute if no exception
-5.0 a/b result in 0
Finally Keyword in Python
Python provides a keyword finally, which is always executed after try and except blocks. The final block always executes after normal termination of try block or after try block terminates due to some exceptions.
try: # Some Code except: # Executed if error in the # try block else: # execute if no exception finally: # Some code .....(always executed)
Can't divide by zero This is always executed
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