JSON for Modern C++  3.5.0

◆ operator[]() [8/8]

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>
const_reference nlohmann::basic_json::operator[] ( const json_pointer ptr) const
inline

Uses a JSON pointer to retrieve a reference to the respective JSON value. No bound checking is performed. The function does not change the JSON value; no null values are created. In particular, the the special value - yields an exception.

Parameters
[in]ptrJSON pointer to the desired element
Returns
const reference to the element pointed to by ptr
Complexity^^ Constant.
Exceptions
parse_error.106if an array index begins with '0'
parse_error.109if an array index was not a number
out_of_range.402if the array index '-' is used
out_of_range.404if the JSON pointer can not be resolved
Example^^ The behavior is shown in the example. ^^ operatorjson_pointer_const.cpp
Output (play with this example online):^^
1
"foo"
[1,2]
2
^^ The example code above can be translated with
g++ -std=c++11 -Isingle_include doc/examples/operatorjson_pointer_const.cpp -o operatorjson_pointer_const 
Since
version 2.0.0

Definition at line 19587 of file json.hpp.