JSON for Modern C++  3.0.1

◆ count()

template<template< typename, typename, typename... > class ObjectType = std::map, template< typename, typename... > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename > class AllocatorType = std::allocator, template< typename, typename=void > class JSONSerializer = adl_serializer>
template<typename KeyT >
size_type nlohmann::basic_json::count ( KeyT &&  key) const
inline

Returns the number of elements with key key. If ObjectType is the default std::map type, the return value will always be 0 (key was not found) or 1 (key was found).

Note
This method always returns 0 when executed on a JSON type that is not an object.
Parameters
[in]keykey value of the element to count
Returns
Number of elements with key key. If the JSON value is not an object, the return value will be 0.
Complexity Logarithmic in the size of the JSON object.
Example The example shows how count() is used. count.cpp Output (play with this example count.link): count.output The example code above can be translated withg++ -std=c++11 -Isrc doc/examples/count.cpp -o count
Since
version 1.0.0

Definition at line 11037 of file json.hpp.