JSON for Modern C++ 2.1.1
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◆ count()

template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > 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 U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
size_type nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer >::count ( typename object_t::key_type  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\n Logarithmic in the size of the JSON object.
Example\n The example shows how count() is used. \n @includelineno count.cpp \n Output (play with this example @htmlinclude count.link):\n @verbinclude count.output \n The example code above can be translated with @verbatim g++ -std=c++11 -Isrc doc/examples/count.cpp -o count @endverbatim
Since
version 1.0.0

Definition at line 4630 of file json.hpp.