JSON for Modern C++ 2.1.1

allocator_type
array
array_t
at
at
at
at
at
at
back
back
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
begin
begin
boolean_t
cbegin
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clear
const_iterator
const_pointer
const_reference
const_reverse_iterator
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detail::external_constructor
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dump
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end
end
erase
erase
erase
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exception
find
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front
front
get
get
get
get
get
get_allocator
get_ptr
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get_ref
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insert
insert
insert
insert
insert
insert
invalid_iterator
is_array
is_boolean
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is_null
is_number
is_number_float
is_number_integer
is_number_unsigned
is_object
is_primitive
is_string
is_structured
iterator
iterator_wrapper
iterator_wrapper
json_serializer
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number_float_t
number_integer_t
number_unsigned_t
object
object_t
operator value_t
operator ValueType
operator!=
operator!=
operator!=
operator+=
operator+=
operator+=
operator+=
operator<
operator<
operator<
operator<<
operator<<
operator<=
operator<=
operator<=
operator=
operator==
operator==
operator==
operator>
operator>
operator>
operator>=
operator>=
operator>=
operator>>
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operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
other_error
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parse
parse
parse
parse
parse
parse
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rbegin
rbegin
reference
rend
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reverse_iterator
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string_t
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swap
swap
to_cbor
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type
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value
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value_t
value_type
~basic_json
| ## ◆ operator[]() [7/10] 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> template<typename T >
reference nlohmann::basic_json::operator[] | ( | T * | key | ) |
| inline
  Returns a reference to the element at with specified key key. Note If key is not found in the object, then it is silently added to the object and filled with a `null` value to make `key` a valid reference. In case the value was `null` before, it is converted to an object. Parameters
  [in] | key | key of the element to access
  Returns reference to the element at key key Exceptions
  type_error.305 | if the JSON value is not an object or null; in that cases, using the [] operator with a key makes no sense.
  Complexity Logarithmic in the size of the container. Example The example below shows how object elements can be read and written using the `[]` operator. 1 #include "json.hpp" 2 #include <iomanip> // for std::setw 3 4 using json = nlohmann::json; 5 6 int main() 7 { 8 // create a JSON object 9 json object = 10 { 11 {"one", 1}, {"two", 2}, {"three", 2.9} 12 }; 13 14 // output element with key "two" 15 std::cout << object["two"] << "\n\n"; 16 17 // change element with key "three" 18 object["three"] = 3; 19 20 // output changed array 21 std::cout << std::setw(4) << object << "\n\n"; 22 23 // mention nonexisting key 24 object["four"]; 25 26 // write to nonexisting key 27 object["five"]["really"]["nested"] = true; 28 29 // output changed object 30 std::cout << std::setw(4) << object << '\n'; 31 } nlohmann::json basic_json<> json default JSON class Definition: json.hpp:13933 Output (play with this example online):
      2

      {
          "one": 1,
          "three": 3,
          "two": 2
      }

      {
          "five": {
              "really": {
                  "nested": true
              }
          },
          "four": null,
          "one": 1,
          "three": 3,
          "two": 2
      }
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/operatorarray__key_type.cpp -o operatorarray__key_type
See also at(const typename object_t::key_type&) for access by reference with range checking value() for access by value with a default value Since version 1.1.0 Definition at line 4224 of file json.hpp.