JSON for Modern C++  3.7.0

◆ swap() [2/4]

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>
void nlohmann::basic_json::swap ( array_t other)
inline

Exchanges the contents of a JSON array with those of other. Does not invoke any move, copy, or swap operations on individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated.

Parameters
[in,out]otherarray to exchange the contents with
Exceptions
type_error.310when JSON value is not an array; example: "cannot use swap() with string"
Complexity
Constant.
Example
The example below shows how arrays can be swapped with swap().
1 #include <iostream>
2 #include <nlohmann/json.hpp>
3 
4 using json = nlohmann::json;
5 
6 int main()
7 {
8  // create a JSON value
9  json value = {{"array", {1, 2, 3, 4}}};
10 
11  // create an array_t
12  json::array_t array = {"Snap", "Crackle", "Pop"};
13 
14  // swap the array stored in the JSON value
15  value["array"].swap(array);
16 
17  // output the values
18  std::cout << "value = " << value << '\n';
19  std::cout << "array = " << array << '\n';
20 }
basic_json<> json
default JSON class
Definition: json.hpp:2355
static basic_json array(initializer_list_t init={})
explicitly create an array from an initializer list
Definition: json.hpp:15905
ArrayType< basic_json, AllocatorType< basic_json > > array_t
a type for an array
Definition: json.hpp:14935
ValueType value(const typename object_t::key_type &key, const ValueType &default_value) const
access specified object element with default value
Definition: json.hpp:17829

Output (play with this example online):
value = {"array":["Snap","Crackle","Pop"]}
array = [1,2,3,4]
The example code above can be translated with
g++ -std=c++11 -Isingle_include doc/examples/swap__array_t.cpp -o swap__array_t 
Since
version 1.0.0

Definition at line 19912 of file json.hpp.