nlohmann::basic_json::operator!=¶
bool operator!=(const_reference lhs, const_reference rhs) noexcept;
template<typename ScalarType>
bool operator!=(const_reference lhs, const ScalarType rhs) noexcept;
template<typename ScalarType>
bool operator!=(ScalarType lhs, const const_reference rhs) noexcept;
Compares two JSON values for inequality by calculating !(lhs == rhs)
.
Template parameters¶
ScalarType
- a scalar type according to
std::is_scalar<ScalarType>::value
Parameters¶
lhs
(in)- first value to consider
rhs
(in)- second value to consider
Return value¶
whether the values lhs
and rhs
are not equal
Exception safety¶
No-throw guarantee: this function never throws exceptions.
Complexity¶
Linear.
Examples¶
Example
The example demonstrates comparing several JSON types.
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
// create several JSON values
json array_1 = {1, 2, 3};
json array_2 = {1, 2, 4};
json object_1 = {{"A", "a"}, {"B", "b"}};
json object_2 = {{"B", "b"}, {"A", "a"}};
json number_1 = 17;
json number_2 = 17.000000000000001L;
json string_1 = "foo";
json string_2 = "bar";
// output values and comparisons
std::cout << std::boolalpha;
std::cout << array_1 << " != " << array_2 << " " << (array_1 != array_2) << '\n';
std::cout << object_1 << " != " << object_2 << " " << (object_1 != object_2) << '\n';
std::cout << number_1 << " != " << number_2 << " " << (number_1 != number_2) << '\n';
std::cout << string_1 << " != " << string_2 << " " << (string_1 != string_2) << '\n';
}
Output:
[1,2,3] != [1,2,4] true
{"A":"a","B":"b"} != {"A":"a","B":"b"} false
17 != 17.0 false
"foo" != "bar" true
Example
The example demonstrates comparing several JSON types against the null pointer (JSON null
).
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
// create several JSON values
json array = {1, 2, 3};
json object = {{"A", "a"}, {"B", "b"}};
json number = 17;
json string = "foo";
json null;
// output values and comparisons
std::cout << std::boolalpha;
std::cout << array << " != nullptr " << (array != nullptr) << '\n';
std::cout << object << " != nullptr " << (object != nullptr) << '\n';
std::cout << number << " != nullptr " << (number != nullptr) << '\n';
std::cout << string << " != nullptr " << (string != nullptr) << '\n';
std::cout << null << " != nullptr " << (null != nullptr) << '\n';
}
Output:
[1,2,3] != nullptr true
{"A":"a","B":"b"} != nullptr true
17 != nullptr true
"foo" != nullptr true
null != nullptr false
Version history¶
- Added in version 1.0.0.
Last update: May 1, 2022