Handling io exception in python
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More Detail IOError Exception It is an error 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. It is also raised for operating system-related errors. If the given code is written in a try block, it raises an input/output exception, which is handled in the except block as shown given below Exampleimport sys def whatever(): try: f = open ( "foo.txt", 'r' ) except IOError, e: print e print sys.exc_type whatever() Output[Errno 2] No such file or directory: 'foo.txt'
Rajendra Dharmkar Updated on 12-Jun-2020 08:08:32
Previous Page Print Page Next Page Advertisements Exceptions in PythonPython has many built-in exceptions that are raised when your program encounters an error (something in the program goes wrong). When these exceptions occur, the Python interpreter stops the current process and passes it to the calling process until it is handled. If not handled, the program will crash. For example, let us consider a program where
we have a function If never handled, an error message is displayed and our program comes to a sudden unexpected halt. Catching Exceptions in PythonIn Python, exceptions
can be handled using a The critical operation which can raise an exception is placed inside the We can thus choose what operations to perform once we have caught the exception. Here is a simple example.
Output The entry is a Oops! In this program, we loop through the values of the randomList list. As previously mentioned, the portion that can
cause an exception is placed inside the If no exception occurs, the Here, we print the name of the exception using the Since every exception in Python inherits from the base
This program has the same output as the above program. Catching Specific Exceptions in PythonIn the above example, we did not mention any specific exception in the This is not a good programming practice as it will catch all exceptions and handle every case in the same way. We can specify which exceptions an A We can use a tuple of values to specify multiple exceptions in an except clause. Here is an example pseudo code.
Raising Exceptions in PythonIn Python programming, exceptions are raised when errors occur at runtime. We can also manually raise exceptions using the We can optionally pass values to the exception to clarify why that exception was raised.
Python try with else clauseIn some situations, you might want to run a certain block of code if the code block inside Note: Exceptions in the else clause are not handled by the preceding except clauses. Let's look at an example:
Output If we pass an odd number: Enter a number: 1 Not an even number! If we pass an even number, the reciprocal is computed and displayed. Enter a number: 4 0.25 However, if we pass 0, we get Enter a number: 0 Traceback (most recent call last): File " Python try...finallyThe For example, we may be connected to a remote data center through the network or working with a file or a Graphical User Interface (GUI). In all these circumstances, we must clean up the resource before the program comes to a halt whether it successfully ran or not. These actions (closing a file, GUI or disconnecting from network) are performed in the Here is an example of file operations to illustrate this.
This type of construct makes sure that the file is closed even if an exception occurs during the program execution. How does Python handle IO exception?IOError in Python is a result of incorrect file name or location. This error is raised in multiple conditions and all these conditions can be handled using try except code block. We saw the working of the error with examples and saw how to avoid it. Implementing try except block will save a lot of hard work.
What is IO error exception in Python?It is an error 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. It is also raised for operating system-related errors.
How does Python handle invalid input?Ask user to enter value again and again if user enter invalid value.. Get input from user by raw_input() (Python 2) or input() (Python 3).. Type of variable name is string , so we have to use string method to valid user enter string.. Use isalpha() string method to check user entered string is valid or not.. How do you handle a runtime error in Python?Errors cannot be handled, while Python exceptions can be handled at the run time. An error can be a syntax (parsing) error, while there can be many types of exceptions that could occur during the execution and are not unconditionally inoperable.
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