Note: this was a bug in the CPython’s handling of yield in comprehensions and generator expressions, fixed in Python 3.8, with a deprecation warning in Python 3.7. See the Python bug report and the What’s New entries for Python 3.7 and Python 3.8. Generator expressions, and set and dict comprehensions are compiled to (generator) function … Read more
Inside a method that returns IEnumerable<T>, yield return has to return T, not an IEnumerable<T>. Replace yield return c.GetDeepControlsByType<T>(); with: foreach (var x in c.GetDeepControlsByType<T>()) { yield return x; }
Update Jan 2021: You can even do it in the Node REPL interactive using –experimental-repl-await flag $ node –experimental-repl-await > const delay = ms => new Promise(resolve => setTimeout(resolve, ms)) > await delay(1000) /// waiting 1 second. A new answer to an old question. Today ( Jan 2017 June 2019) it is much easier. You … Read more
Generators can’t be rewound. You have the following options: Run the generator function again, restarting the generation: y = FunctionWithYield() for x in y: print(x) y = FunctionWithYield() for x in y: print(x) Store the generator results in a data structure on memory or disk which you can iterate over again: y = list(FunctionWithYield()) for … Read more
Let’s get one thing out of the way first. The explanation that yield from g is equivalent to for v in g: yield v does not even begin to do justice to what yield from is all about. Because, let’s face it, if all yield from does is expand the for loop, then it does … Read more
I think the accepted answer is great, but it seems many people have failed to grasp some fundamental points. First, Scala’s for comprehensions are equivalent to Haskell’s do notation, and it is nothing more than a syntactic sugar for composition of multiple monadic operations. As this statement will most likely not help anyone who needs … Read more
The yield contextual keyword actually does quite a lot here. The function returns an object that implements the IEnumerable<object> interface. If a calling function starts foreaching over this object, the function is called again until it “yields”. This is syntactic sugar introduced in C# 2.0. In earlier versions you had to create your own IEnumerable … Read more