Implementing class-based callbacks in Python (Python)

2017-04-20T23:34:50-07:00

Python recipe 580788 by Vasudev Ram (callbacks, classes, functions, methods, objects, programming, python).

This is a follow-on to this recently posted recipe:

Implementing function-based callbacks in Python: https://code.activestate.com/recipes/580787-implementing-function-based-callbacks-in-python/?in=user-4173351

This new recipe shows how to create and use callbacks in Python, using classes with methods, instead of plain functions, as was done in the recipe linked above. All other points such as reasons and benefits for using callbacks, are more or less the same as mentioned in the previous recipe, except that class instances can carry state around, so to that extent, the two approaches are different.

https://jugad2.blogspot.in/2017/04/python-callbacks-using-classes-and.html

Humanize decorator (Python)

2013-07-31T16:04:13-07:00

Python recipe 578619 by tomer filiba (decorator, objects, pretty, print).

When you need to inspect Python objects in a human-readable way, you're usually required to implement a custom __str__ or __repr__ which are just boilerplate (e.g., return "Foo(%r, %r, %r)" % (self.bar, self.spam, self.eggs). You may implement __str__ and __repr__ by a base-class, but it's hard to call it inheritance and moreover, you may wish to remove it when you're done debugging.

This simple (yet complete) recipe is a class decorator that injects __str__ and __repr__ into the class being printed. It handles nesting and even cycle detection, allowing you to just plug it into existing classes to get them pretty-printed and perhaps remove it later.

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Implementing class-based callbacks in Python (Python)

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