allocator_type
array
array_t
at
at
at
at
back
back
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
begin
begin
boolean_t
cbegin
cend
clear
const_pointer
const_reference
count
crbegin
crend
difference_type
dump
empty
end
end
erase
erase
erase
erase
find
find
front
front
get
get
get
get_allocator
get_ptr
get_ptr
is_array
is_boolean
is_discarded
is_null
is_number
is_number_float
is_number_integer
is_object
is_primitive
is_string
is_structured
max_size
number_float_t
number_integer_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[]
parse
parse
parse_event_t
parser_callback_t
pointer
push_back
push_back
push_back
rbegin
rbegin
reference
rend
rend
size
size_type
string_t
swap
swap
swap
swap
type
value_t
value_type
~basic_json

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 = int64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator>

reference nlohmann::basic_json::operator[] | ( | const typename object_t::key_type & | 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

  std::domain_error | if JSON is not an object or null

Complexity
  Logarithmic in the size of the container.

Example
  The example below shows how object elements can be read and written using the [] operator.
  #include <json.hpp>
  using namespace nlohmann;
  int main()
  {
  // create a JSON object
  json object =
  {
  {"one", 1}, {"two", 2}, {"three", 2.9}
  };
  // output element with key "two"
  std::cout << object["two"] << "\n\n";
  // change element with key "three"
  object["three"] = 3;
  // output changed array
  std::cout << std::setw(4) << object << "\n\n";
  // mention nonexisting key
  object["four"];
  // write to nonexisting key
  object["five"]["really"]["nested"] = true;
  // output changed object
  std::cout << std::setw(4) << object << '\n';
  }
  nlohmann::basic_json
  a class to store JSON values
  Definition: json.hpp:130
  nlohmann
  namespace for Niels Lohmann
  Definition: json.hpp:55
  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