Matlab与Python中yield关键字的等效项是什么?

本文介绍了Matlab与Python中yield关键字的等效项是什么?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我需要一次生成多个结果，而不是一次生成所有结果.

I need to generate multiple results but one at a time, as opposed to everything at once in an array.

我如何在Matlab中使用像Python这样的语法生成器来做到这一点?

How do I do that in Matlab with a generator like syntax as in Python?

推荐答案

在执行使用yield关键字的函数时，它们实际上返回一个生成器.生成器是迭代器的一种.尽管MATLAB都不提供语法，但是您可以自己实现迭代器接口" .这是类似于python中的xrange函数的示例:

When executing functions that use the yield keyword, they actually return a generator. Generators are a type of iterators. While MATLAB does not provide the syntax for either, you can implement the "iterator interface" yourself. Here is an example similar to xrange function in python:

classdef rangeIterator < handle properties (Access = private) i n end methods function obj = rangeIterator(n) obj.i = 0; obj.n = n; end function val = next(obj) if obj.i < obj.n val = obj.i; obj.i = obj.i + 1; else error('Iterator:StopIteration', 'Stop iteration') end end function reset(obj) obj.i = 0; end end end

这是我们使用迭代器的方式:

Here is how we use the iterator:

r = rangeIterator(10); try % keep call next() method until it throws StopIteration while true x = r.next(); disp(x); end catch ME % if it is not the "stop iteration" exception, rethrow it as an error if ~strcmp(ME.identifier,'Iterator:StopIteration') rethrow(ME); end end

请注意，当在Python中的迭代器上使用构造for .. in ..时，它在内部会执行类似的操作.

Note the when using the construct for .. in .. in Python on iterators, it internally does a similar thing.

通过使用persistent变量或闭包来存储函数的局部状态，您可以使用常规函数而不是类编写类似的内容，并在每次调用时返回中间结果".

You could write something similar using regular functions instead of classes, by using either persistent variables or a closure to store the local state of the function, and return "intermediate results" each time it is called.