generator

问题 I have been trying to understand asynchronous programming, particularly in Python. I understand that asyncio is built off of an event loop which schedules the execution of coroutines, but I have read about several different ways to define coroutines, and I am confused how they all relate to each other. I read this article for more background information on the topic. Although it covers each of the four types of coroutines I have mentioned, it does not entirely describe how they differ.

问题 i am running the notebook at this site https://github.com/vsmolyakov/experiments_with_python/blob/master/chp01/ensemble_methods.ipynb to practice ensemble methods with python, and getting an error when running this part of the code in python 3: plt.figure() (_, caps, _) = plt.errorbar(num_est, bg_clf_cv_mean, yerr=bg_clf_cv_std, c='blue', fmt='-o', capsize=5) for cap in caps: cap.set_markeredgewidth(1) plt.ylabel('Accuracy'); plt.xlabel('Ensemble Size'); plt.title('Bagging Tree Ensemble');

问题 I'm intending to implement a random number generator via Swift 3. I have three different methods for generating an integer (between 0 and 50000 ) ten thousand times non-stop. Do these generators use the same math principles of generating a value or not? What generator is less CPU and RAM intensive at runtime (having 10000 iterations)? method A : var generator: Int = random() % 50000 method B : let generator = Int(arc4random_uniform(50000)) method C : import GameKit let number: [Int] = [0, 1,

问题 Let F[q^p] be a finite cyclic set of polynomials, where q is a prime number and p is an integer greater than 0. Each element in F[q^p] will be a polynomial up to degree (p-1) under (mod q). Ex: F[2^2]={0,1,x,1+x} Ex: F[3^4]={0,1,2,0+x,1+x,2+x,0+x^2,1+x^2,2+x^2,x+x^2,1+x+x^2,2+x+x^2,2x+x^2,1+2x+x^2,2+2x+x^2,0+2x^2,1+2x^2,2+2x^2,x+2x^2,1+x+2x^2,2+x+2x^2,2x+2x^2,1+2x+2x^2,2+2x+2x^2,...,2+2x+2x^2+2x^3} Thus, there will be q^p elements in F[q,p]. Assume that we have a generator theta, where theta

问题 Is there a one-line expression for: for thing in generator: yield thing I tried yield generator to no avail. 回答1: In Python 3.3+, you can use yield from. For example, >>> def get_squares(): ... yield from (num ** 2 for num in range(10)) ... >>> list(get_squares()) [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] It can actually be used with any iterable. For example, >>> def get_numbers(): ... yield from range(10) ... >>> list(get_numbers()) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> def get_squares(): ... yield

问题 Is there a one-line expression for: for thing in generator: yield thing I tried yield generator to no avail. 回答1: In Python 3.3+, you can use yield from. For example, >>> def get_squares(): ... yield from (num ** 2 for num in range(10)) ... >>> list(get_squares()) [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] It can actually be used with any iterable. For example, >>> def get_numbers(): ... yield from range(10) ... >>> list(get_numbers()) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> def get_squares(): ... yield

问题 I'm using python and I'm trying to find a way to elegantly chain multiple generators together. An example of the problem would be having for instance a root generator which provides some kind of data and each value being passed to its "children" like a cascade which in turn may modify the object they receive. I could go for this route: for x in gen1: gen2(x) gen3(x) But it's ugly and not elegant. I was thinking about a more functional way of doing things. 回答1: You could turn the generators

问题 In TypeScript (3.6.3) Generator<> is almost identical to IterableIterator<> . When Generator<> extends Iterator<> , it defaults the third generic argument (TNext) to unknown . Iterator<> by itself defaults TNext to undefined . So Generator and Iterator (and IterableIterator ) don't line up as well as they might should. let gen2:IterableIterator<string>; function* gen1():Generator<string> { yield* gen2; } The yield* line is an error: "Cannot delegate iteration to value because the 'next'

问题 In TypeScript (3.6.3) Generator<> is almost identical to IterableIterator<> . When Generator<> extends Iterator<> , it defaults the third generic argument (TNext) to unknown . Iterator<> by itself defaults TNext to undefined . So Generator and Iterator (and IterableIterator ) don't line up as well as they might should. let gen2:IterableIterator<string>; function* gen1():Generator<string> { yield* gen2; } The yield* line is an error: "Cannot delegate iteration to value because the 'next'

问题 In TypeScript (3.6.3) Generator<> is almost identical to IterableIterator<> . When Generator<> extends Iterator<> , it defaults the third generic argument (TNext) to unknown . Iterator<> by itself defaults TNext to undefined . So Generator and Iterator (and IterableIterator ) don't line up as well as they might should. let gen2:IterableIterator<string>; function* gen1():Generator<string> { yield* gen2; } The yield* line is an error: "Cannot delegate iteration to value because the 'next'