A more “batteries-included” implementation of this kind of thing, including language support, is now available as of C# 8.0. Now, when using at least C# 8.0 (or higher) with .NET Standard 2.1 (or higher) and/or .NET Core 3.0 (or higher), the code from the original question may be written as follows: private async IAsyncEnumerable<char> TestAsync(string … Read more
Yes, since C++11 there are the two methods you are looking for called std::prev and std::next. You can find them in the iterator library. Example from cppreference.com #include <iostream> #include <iterator> #include <list> int main() { std::list<int> v{ 3, 1, 4 }; auto it = v.begin(); auto nx = std::next(it, 2); std::cout << *it << … Read more
In short: An Iterator does have state, whereas an Iterable does not. See the API docs for both. Iterable: A base trait for iterable collections. This is a base trait for all Scala collections that define an iterator method to step through one-by-one the collection’s elements. […] This trait implements Iterable’s foreach method by stepping … Read more
Use the old for loop as: for (auto it = values.begin(); it != values.end(); ++it ) { auto & value = *it; //… } With this, you’ve value as well as iterator it. Use whatever you want to use. EDIT: Although I wouldn’t recommended this, but if you want to use range-based for loop (yeah, … Read more
Calls to itertools.imap() in Python 2 or map() in Python 3 can be replaced by equivalent generator expressions: sum(1 for dummy in it) This also uses a lazy generator, so it avoids materializing a full list of all iterator elements in memory.
The alternative to catching StopIteration is to use next(iterator, default_value). For example: >>> a = iter(‘hi’) >>> print(next(a, None)) h >>> print(next(a, None)) i >>> print(next(a, None)) None This way you can check for None to see if you’ve reached the end of the iterator if you don’t want to do it the exception way. … Read more
I don’t know of any implementation in a major library, but it looked like an interesting problem so I wrote a basic implementation. I’ve only tested it with the test case I present here, so I don’t recommend using it without further testing. The problem is a bit trickier than it looks because some of … Read more
Firstly, your “messy way” is ok, there’s nothing wrong with using indices into the dataframe, and this will not be too slow. iterrows() itself isn’t terribly fast. A version of your first idea that would work would be: row_iterator = df.iterrows() _, last = row_iterator.next() # take first item from row_iterator for i, row in … Read more
For known module, just separate them by commas: import lib1, lib2, lib3, lib4, lib5 If you really need to programmatically import based on dynamic variables, a literal translation of your ruby would be: modnames = “lib1 lib2 lib3 lib4 lib5”.split() for lib in modnames: globals()[lib] = __import__(lib) Though there’s no need for this in your … Read more