Can’t set attributes on instance of “object” class
So, I was playing around with Python while answering this question, and I discovered that this is not valid:
language-design
Why does Python assignment not return a value?
Why is Python assignment a statement rather than an expression? If it was an expression which returns the value of the right hand side in the assignment, it would have allowed for much less verbose code in some cases. Are there any issues I can’t see?
Why doesn’t a python dict.update() return the object?
I ‘m trying to do :
Read/Write Python Closures
Closures are an incredibly useful language feature. They let us do clever things that would otherwise take a lot of code, and often enable us to write code that is more elegant and more clear. In Python 2.x, closures variable names cannot be rebound; that is, a function defined inside another lexical scope cannot do something like some_var = 'changed!' for variables outside of its local scope. Can someone explain why that is? There have been situations in which I would like to create a closure that rebinds variables in the outer scope, but it wasn’t possible. I realize that in almost all cases (if not all of them), this behavior can be achieved with classes, but it is often not as clean or as elegant. Why can’t I do it with a closure?
Why are slice and range upper-bound exclusive?
Disclaimer: I am not asking if the upper-bound stopargument of slice()and range() is exclusive or how to use these functions.
What’s the difference between __builtin__ and __builtins__?
I was coding today and noticed something. If I open a new interpreter session (IDLE) and check what’s defined with the dir function I get this:
Why are default arguments evaluated at definition time?
I had a very difficult time with understanding the root cause of a problem in an algorithm. Then, by simplifying the functions step by step I found out that evaluation of default arguments in Python doesn’t behave as I expected.
Which classes cannot be subclassed?
Is there any rule about which built-in and standard library classes are not subclassable (“final”)?
Why doesn’t Python have a sign function?
I can’t understand why Python doesn’t have a sign function. It has an abs builtin (which I consider sign‘s sister), but no sign.
Why does Python’s itertools.permutations contain duplicates? (When the original list has duplicates)
It is universally agreed that a list of n distinct symbols has n! permutations. However, when the symbols are not distinct, the most common convention, in mathematics and elsewhere, seems to be to count only distinct permutations. Thus the permutations of the list [1, 1, 2] are usually considered to be
[1, 1, 2], [1, 2, 1], [2, 1, 1]. Indeed, the following C++ code prints precisely those three: