sum

Computes sum of a sequence of values. More...

Functions
template<typename F >
auto	coveo::linq::sum (const F &num_f) -> detail::sum_impl< F >
	Computes sum using numerical function. More...

Detailed Description

The sum operator computes the sum of all values in a sequence. To achieve this, it needs a numerical function to extract a numeric value from each sequence element.

This is a terminal operator.

.NET equivalent: Sum

Function Documentation

sum()

template<typename F >

auto coveo::linq::sum

(

const F &

num_f

)

-> detail::sum_impl<F>

Computes the sum of all elements in a sequence by repeatedly calling a numerical function. The function receives an element as parameter and must return a numerical value for the element. The final result is the sum of all such numerical values.

Does not work on empty sequences.

Use like this:

const std::vector<std::string> STRS = { "42", "23", "66" };

using namespace coveo::linq;
auto tot = from(STRS)
         | sum([](auto&& s) { return std::stoi(s); });
// tot == 131

Parameters

num_f

Function to get numerical value for each element.

Returns

(Once applied) Sum of all extracted numerical values.

Exceptions

coveo::linq::empty_sequence

The sequence contains no elements.