JSON for Modern C++ 3.0

- Main Page
- Related Pages
- Classes

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>
const_reference nlohmann::basic_json::at | ( | const typename object_t::key_type & | key | ) | const
| inline
  Returns a const reference to the element at with specified key key, with bounds checking. Parameters
  [in] | key | key of the element to access
  Returns const reference to the element at key key Exceptions
  std::domain_error | if JSON is not an object
  std::out_of_range | if the key key is is not stored in the object; that is, `find(key) == end()`
  Complexity Logarithmic in the size of the container. Example The example below shows how object elements can be read using at. 1 #include <json.hpp> 2 3 using namespace nlohmann; 4 5 int main() 6 { 7 // create JSON object 8 json object = 9 { 10 {"the good", "il buono"}, 11 {"the bad", "il cativo"}, 12 {"the ugly", "il brutto"} 13 }; 14 15 // output element with key "the ugly" 16 std::cout << object.at("the ugly") << '\n'; 17 18 // try to read from a nonexisting key 19 try 20 { 21 std::cout << object.at("the fast") << '\n'; 22 } 23 catch (std::out_of_range) 24 { 25 std::cout << "out of range" << '\n'; 26 } 27 } nlohmann::basic_json a class to store JSON values Definition: json.hpp:130 nlohmann::basic_json::at reference at(size_type idx) access specified array element with bounds checking Definition: json.hpp:2412 nlohmann namespace for Niels Lohmann Definition: json.hpp:55 Output (play with this example online):
      "il brutto"
      out of range
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/at__object_t_key_type_const.cpp -o at__object_t_key_type_const