update() [1/2]

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, class BinaryType = std::vector<std::uint8_t>>

void nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType >::update ( const_iterator  first, const_iterator  last  )

inline

updates a JSON object from another object, overwriting existing keys

Inserts all values from from range [first, last) and overwrites existing keys.

Parameters

[in]	first	begin of the range of elements to insert
[in]	last	end of the range of elements to insert

Exceptions

type_error.312	if called on JSON values other than objects; example: "cannot use update() with string"
invalid_iterator.202	if iterator first or last does does not point to an object; example: "iterators first and last must point to objects"
invalid_iterator.210	if first and last do not belong to the same JSON value; example: "iterators do not fit"

@complexity O(N*log(size() + N)), where N is the number of elements to insert.

@liveexample{The example shows how update() is used__range.,update}

See also

https://docs.python.org/3.6/library/stdtypes.html#dict.update

Since

version 3.0.0

Definition at line 23748 of file json.hpp.

    {
        // implicitly convert null value to an empty object
        if (is_null())
        {
            m_type = value_t::object;
            m_value.object = create<object_t>();
            assert_invariant();
        }
 
        if (JSON_HEDLEY_UNLIKELY(!is_object()))
        {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name()), *this));
        }
 
        // check if range iterators belong to the same JSON object
        if (JSON_HEDLEY_UNLIKELY(first.m_object != last.m_object))
        {
            JSON_THROW(invalid_iterator::create(210, "iterators do not fit", *this));
        }
 
        // passed iterators must belong to objects
        if (JSON_HEDLEY_UNLIKELY(!first.m_object->is_object()
                                 || !last.m_object->is_object()))
        {
            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects", *this));
        }
 
        for (auto it = first; it != last; ++it)
        {
            m_value.object->operator[](it.key()) = it.value();
#if JSON_DIAGNOSTICS
            m_value.object->operator[](it.key()).m_parent = this;
#endif
        }
    }