idiomatic

I'm looking for a better/more Pythonic solution for the following snippet count = sum(1 for e in iterable if e) len(filter(None, iterable)) Using None as the predicate for filter just says to use the truthiness of the items. (maybe clearer would be len(filter(bool, iterable)) ) Honestly, I can't think of a better way to do it than what you've got. Well, I guess people could argue about "better," but I think you're unlikely to find anything shorter, simpler, and clearer. Most Pythonic is to write a small auxiliary function and put it in your trusty "utilities" module (or submodule of

I recently forced myself to study C++ and I just finished reading the book C++: The Complete Reference, by Herbert Schildt. I liked the book and think I got more or less the big picture. I noticed though that when I try to check with other people the things I code using the material I learned, they are usually considered non-idiomatic and superseded by an STL way to do it that is safer and easier (well, the book doesn't cover STL and Boost libraries). So I'd like to ask: what are good sources to learn the patterns of a good C++ program? Where can I learn basic patterns from the "C++ way" to do

I'm writing C++ code in an environment in which I don't have access to the C++ standard library, specifically not to std::numeric_limits . Suppose I want to implement template <typename T> constexpr T all_ones( /* ... */ ) Focusing on unsigned integral types, what do I put there? Specifically, is static_cast<T>(-1) good enough? (Other types I could treat as an array of unsigned chars based on their size I guess.) Leandros Use the bitwise NOT operator ~ on 0 . T allOnes = ~(T)0; A static_cast<T>(-1) assumes two's complement, which is not portable. If you are only concerned about unsigned types,

Suppose I have the class class A { protected: int x,y; double z,w; public: void foo(); void bar(); void baz(); }; defined and used in my code and the code of others. Now, I want to write some library which could very well operate on A's, but it's actually more general, and would be able to operate on: class B { protected: int y; double z; public: void bar(); }; and I do want my library to be general, so I define a B class and that's what its APIs take. I would like to be able to tell the compiler - not in the definition of A which I no longer control, but elsewhere, probably in the definition

I'm trying to search a scala collection for an item in a list that matches some predicate. I don't necessarily need the return value, just testing if the list contains it. In Java, I might do something like: for ( Object item : collection ) { if ( condition1(item) && condition2(item) ) { return true; } } return false; In Groovy, I can do something like: return collection.find { condition1(it) && condition2(it) } != null What's the idiomatic way to do this in Scala? I could of course convert the Java loop style to Scala, but I feel like there's a more functional way to do this. Use filter: