JSON for Modern C++ 2.0.10

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
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
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basic_json
basic_json
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basic_json
basic_json
begin
begin
boolean_t
cbegin
cend
clear
const_iterator
const_pointer
const_reference
const_reverse_iterator
count
crbegin
crend
diff
difference_type
dump
emplace
emplace_back
empty
end
end
erase
erase
erase
erase
find
find
flatten
from_cbor
from_msgpack
front
front
get
get
get
get_allocator
get_ptr
get_ptr
get_ref
get_ref
insert
insert
insert
insert
insert
is_array
is_boolean
is_discarded
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
max_size
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[]
operator[]
operator[]
operator[]
operator[]
parse
parse
parse
parse
parse
parse
parse_event_t
parser_callback_t
patch
pointer
push_back
push_back
push_back
push_back
rbegin
rbegin
reference
rend
rend
reverse_iterator
size
size_type
string_t
swap
swap
swap
swap
to_cbor
to_msgpack
type
unflatten
value
value
value
value
value_t
value_type
~basic_json
| ## § operator[]() [9/10] 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>
reference nlohmann::basic_json::operator[] | ( | const json_pointer & | ptr | ) |
| inline
  Uses a JSON pointer to retrieve a reference to the respective JSON value. No bound checking is performed. Similar to operator[](const typename object_t::key_type&), `null` values are created in arrays and objects if necessary. In particular: If the JSON pointer points to an object key that does not exist, it is created an filled with a `null` value before a reference to it is returned. If the JSON pointer points to an array index that does not exist, it is created an filled with a `null` value before a reference to it is returned. All indices between the current maximum and the given index are also filled with `null`. The special value `-` is treated as a synonym for the index past the end. Parameters
  [in] | ptr | a JSON pointer
  Returns reference to the element pointed to by ptr Complexity Constant. Exceptions
  std::out_of_range | if the JSON pointer can not be resolved
  std::domain_error | if an array index begins with '0'
  std::invalid_argument | if an array index was not a number
  Example The behavior is shown in the example. 1 #include <json.hpp> 2 3 using json = nlohmann::json; 4 5 int main() 6 { 7 // create a JSON value 8 json j = 9 { 10 {"number", 1}, {"string", "foo"}, {"array", {1, 2}} 11 }; 12 13 // read-only access 14 15 // output element with JSON pointer "/number" 16 std::cout << j["/number"_json_pointer] << '\n'; 17 // output element with JSON pointer "/string" 18 std::cout << j["/string"_json_pointer] << '\n'; 19 // output element with JSON pointer "/array" 20 std::cout << j["/array"_json_pointer] << '\n'; 21 // output element with JSON pointer "/array/1" 22 std::cout << j["/array/1"_json_pointer] << '\n'; 23 24 // writing access 25 26 // change the string 27 j["/string"_json_pointer] = "bar"; 28 // output the changed string 29 std::cout << j["string"] << '\n'; 30 31 // "change" a nonexisting object entry 32 j["/boolean"_json_pointer] = true; 33 // output the changed object 34 std::cout << j << '\n'; 35 36 // change an array element 37 j["/array/1"_json_pointer] = 21; 38 // "change" an array element with nonexisting index 39 j["/array/4"_json_pointer] = 44; 40 // output the changed array 41 std::cout << j["array"] << '\n'; 42 43 // "change" the array element past the end 44 j["/array/-"_json_pointer] = 55; 45 // output the changed array 46 std::cout << j["array"] << '\n'; 47 } nlohmann::json basic_json<> json default JSON class Definition: json.hpp:12151 Output (play with this example online):
      1
      "foo"
      [1,2]
      2
      "bar"
      {"array":[1,2],"boolean":true,"number":1,"string":"bar"}
      [1,21,null,null,44]
      [1,21,null,null,44,55]
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/operatorjson_pointer.cpp -o operatorjson_pointer
Since version 2.0.0 Definition at line 11522 of file json.hpp.