Comments on: How to Retrieve the Firsts from a Collection of Pairs

By: jft

jft — Sun, 11 Nov 2018 13:01:00 +0000

Yeah – A lambda can take an auto parameter whereas a function can’t. Nice one! 🙂

By: Jonathan Boccara

Jonathan Boccara — Sat, 10 Nov 2018 19:18:00 +0000

In reply to dslater. I might have been wrong here, but the point of the lambda is that we can pass it to the algorithm, which we can't for a function in this case because it would have been a template function. We would have had to specify the template type parameter (here the type of the pair) at call site. Does this seem reasonable to you?

By: jft

jft — Sat, 10 Nov 2018 15:33:00 +0000

In reply to dslater. I would have considered this for a lambda rather than a function only if I wanted the lambda to be specific to a function - as C++ doesn't allow nested functions.

By: dslater

dslater — Sat, 10 Nov 2018 14:34:00 +0000

Defining get_first I the util namespace with a lambda that captures nothing is just silly. It should just be defined as a normal named function.

By: Shreyans

Shreyans — Sat, 10 Nov 2018 06:39:00 +0000

Ranges are great for such transformations. It just makes the code so elegant..

By: Piotr Nycz

Piotr Nycz — Fri, 09 Nov 2018 07:55:00 +0000

Interesting idea with defining function as variable (Utinls::get_first) (+1). I would try to make it constexpr. But defining it as functor class with operator() template would give the possibility for specializing that operator for various types? it is not possible for lambda. BTW – since C++17 `using std::get; return get(obj);` is more canonical form of getting first element – works for pair, tuple, array