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>
Clears the content of a JSON value and resets it to the default value as if basic_json(value_t) would have been called with the current value type from type():
Value type | initial value |
null | null |
boolean | false |
string | "" |
number | 0 |
object | {} |
array | [] |
- Postcondition
- Has the same effect as calling
- Example^^ The example below shows the effect of clear() to different
- JSON types. ^^
2 #include <nlohmann/json.hpp> 10 json j_boolean =
true;
11 json j_number_integer = 17;
12 json j_number_float = 23.42;
13 json j_object = {{
"one", 1}, {
"two", 2}};
14 json j_array = {1, 2, 4, 8, 16};
15 json j_string =
"Hello, world";
20 j_number_integer.clear();
21 j_number_float.clear();
27 std::cout << j_null <<
'\n';
28 std::cout << j_boolean <<
'\n';
29 std::cout << j_number_integer <<
'\n';
30 std::cout << j_number_float <<
'\n';
31 std::cout << j_object <<
'\n';
32 std::cout << j_array <<
'\n';
33 std::cout << j_string <<
'\n';
basic_json<> json
default JSON class
Output (play with this example online):^^ null
false
0
0.0
{}
[]
""
^^ The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/clear.cpp -o clear
- Complexity^^ Linear in the size of the JSON value.
- Iterator validity^^ All iterators, pointers and references related to this container
- are invalidated.
- Exception safety^^ No-throw guarantee: this function never throws exceptions.
- See also
- basic_json(value_t) – constructor that creates an object with the same value than calling
clear()
- Since
- version 1.0.0
Definition at line 17047 of file json.hpp.