Tag: exception

How do I raise the same Exception with a custom message in Python?

I have this try block in my code: Strictly speaking, I am actually raising another ValueError, not the ValueError thrown by do_something…(), which is referred to as err in this case. How do I attach a custom message to err? I try the following code but fails due to err, a ValueError instance, not being …

Logging uncaught exceptions in Python

exception logging python

How do you cause uncaught exceptions to output via the logging module rather than to stderr? I realize the best way to do this would be: But my situation is such that it would be really nice if logging.exception(…) were invoked automatically whenever an exception isn’t caught. Answer As Ned pointe…

What is the use of “assert” in Python?

assert assertion exception python

What does assert mean? How is it used? Answer The assert statement exists in almost every programming language. It has two main uses: It helps detect problems early in your program, where the cause is clear, rather than later when some other operation fails. A type error in Python, for example, can go through…

How can I write a `try`/`except` block that catches all exceptions?

exception python

How can I write a try/except block that catches all exceptions? Answer You can but you probably shouldn’t: However, this will also catch exceptions like KeyboardInterrupt and you usually don’t want that, do you? Unless you re-raise the exception right away – see the following example from th…

How to check that a regular expression has matched a string completely, i.e. – the string did not contain any extra character?

error-handling exception python regex

I have two questions: 1) I have a regular expression ([A-Z][a-z]{0,2})(d*) and I am using Python’s re.finditer() to match appropriate strings. My problem is, that I want to match only strings that contain no extra characters, otherwise I want to raise an exception. I want to catch a following pattern: &…