built-in

来源： https://stackoverflow.com/questions/64611050/python-change-exception-printable-output-eg-overload-builtins

来源： https://stackoverflow.com/questions/64611050/python-change-exception-printable-output-eg-overload-builtins

来源： https://stackoverflow.com/questions/63604914/how-can-i-speed-up-the-binary-gcd-algorithm-using-builtin-ctz

来源： https://stackoverflow.com/questions/63604914/how-can-i-speed-up-the-binary-gcd-algorithm-using-builtin-ctz

问题 is there a feautre similar to C macros which lets you reuse code in an inline manner, without creating a seperate scope for that piece of code? for example: a=3 def foo(): a=4 foo() print a will print 3, however i want it to print 4. i am aware of solutions involving objects like classes or a global dict, however i'm looking for a more primitive solution (like a function decorator for example) that would simply let me make changes inside the scope of the caller instead. thank you very much

问题 I wrote a class to represent vectors in Python (as an exercise) and I'm having problems with extending the built-in operators. I defined a __mul__ method for the vector class. The problem is that in the expression x * y the interpreter calls the __mul__ method of x, not y. So vector(1, 2, 3) * 2 returns a vector <2, 4, 6> just like it should; but 2 * vector(1, 2, 3) creates a TypeError because the built-in int class does not support multiplication by my user-defined vectors. I could solve

问题 I wrote a class to represent vectors in Python (as an exercise) and I'm having problems with extending the built-in operators. I defined a __mul__ method for the vector class. The problem is that in the expression x * y the interpreter calls the __mul__ method of x, not y. So vector(1, 2, 3) * 2 returns a vector <2, 4, 6> just like it should; but 2 * vector(1, 2, 3) creates a TypeError because the built-in int class does not support multiplication by my user-defined vectors. I could solve

问题 I am trying to make an alias that overrides the cd command. This is going to execute a script before and after the "real" cd . Here is what I have so far: alias cd="echo before; cd $1; echo after" This executes the echo before and echo after command however it always changes directory ~ How would I fix this? I also tried cd(){ echo before; cd $1; echo after; } however it repetedly echos "before". 回答1: I also tried cd(){ echo before; cd $1; echo after; } however it repetedly echos "before".

问题 I am trying to make an alias that overrides the cd command. This is going to execute a script before and after the "real" cd . Here is what I have so far: alias cd="echo before; cd $1; echo after" This executes the echo before and echo after command however it always changes directory ~ How would I fix this? I also tried cd(){ echo before; cd $1; echo after; } however it repetedly echos "before". 回答1: I also tried cd(){ echo before; cd $1; echo after; } however it repetedly echos "before".

问题 For example, if you have n lists of bools of the same length, then elementwise boolean AND should return another list of that length that has True in those positions where all the input lists have True, and False everywhere else. It's pretty easy to write, i just would prefer to use a builtin if one exists (for the sake of standardization/readability). Here's an implementation of elementwise AND: def eAnd(*args): return [all(tuple) for tuple in zip(*args)] example usage: >>> eAnd([True, False