Use this tag for questions related to nlohmann JSON C++ library
nlohmann JSON is a header-only JSON class for Modern C++ (C++11)
Latest release: 3.9.1 released on 2020-08-06
See the github project
Questions tagged [nlohmann-json]
248 questions
1
vote
0 answers
trying to include nlohmann/json.hpp
OS environment is Centos 8 g++ version 8.5
and for Ubuntu 22.0 g++ 11.3.0
I have a nagging issue, which doesn't rear its head when I build on Ubuntu.
I'm finding that for my centos build in order for the the compiler to find the 'json.hpp'
I have to…
monkeybrains
- 31
- 2
1
vote
0 answers
json nlohmann converting json to structure with char* types
I have the following code which works fine with a basic stucture containing an int and std::string types. I have made a custom helper to convert the raw json to my structure type.
#include
#include
#include…
user2020
- 217
- 2
- 12
1
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1 answer
when running a function from my project, the stod() function gives an incorrect result
I have three files - a json file, my project, and test (main.cpp)
json file:
{
"points": {
"range": 25,
"step": 0.001
}
}
in file main.cpp this code:
#include
#include
#include
#include…
frnzzz
- 11
- 2
1
vote
1 answer
OvenMediaEngine Answer Sdp parsing error: a=group:LS locQqN
I cannot connect to OvenMediaEngine server with a libdatachannel library. When I send answer message it returns Could not parse SDP error. I can't find true format of answer type message.
I sent request offer with:
{"command",…
Nuri Akın
- 13
- 4
1
vote
1 answer
How to get the data after parsing json created using nlohmann json
I have a requirement to store two structure namely one and two in Json in following format, and then parse this JSON and store the data back to those structure object.
{ "One",{
{ "Value1", one.Value1() },
}
},
{ "Two",{
…
user2094814
- 27
- 1
- 1
- 7
1
vote
1 answer
access array using 'nlohmann' JSON parser
I am trying to access an JSON array using 'nlohmann' library, as the example below shows:
#include
#include
#include "json.hpp"
using json = nlohmann::json;
int main() {
{
const std::string str(
R"(
{
…
canellas
- 491
- 5
- 17
1
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1 answer
user writes access path to a nested element in a JSON file
I wrote a code that prompts the user for the access path to an element in a JSON file and then retrieves the value of that element. But I can only get access to a root element. What should user write to e.g. get object.array[2].field? I use single…
Plateau
- 13
- 3
1
vote
1 answer
JSON output differs between gcc and MSVC
The below code snippet is using nlohmann-json library.
However the output differs between MSVC and GCC compilers (both compiled using -std=c++14).
MSVC outputs:
{"test":[]}
gcc outputs:
{"test":[[]]}
Code snippet:
#include…
Constantin
- 8,721
- 13
- 75
- 126
1
vote
1 answer
C++ Json parsing issue throws Unhandled Exception
``
I am trying to order a vector of coins to be traded in order of their market cap rank. it compiles perfectly and runs but throws an error 3 at runtime. code found below.
debugging: json.hpp Throws unhandled exception
Unhandled exception at…
John Doe
- 47
- 6
1
vote
1 answer
Iterate using iterators on nlohmann::json? Error: invalid_iterator
Continuing my previous question here, Now I want to insert the keys and values present in the below json into a std::vector>> vec;
Keys here are this strings: 12CUDzb3oe8RBQ4tYGqsuPsCbsVE4KWfktXRihXf8Ggq…
Senor Maldona
- 55
- 6
1
vote
0 answers
Translate nlohmann into json to torch tensor
I have this code with specific hard-coded dimension and dimensionality
auto x_data=json_data.at("x").get>>();
auto x_options = torch::TensorOptions().dtype(at::kFloat);
torch::Tensor x_tensor =…
Fzza
- 105
- 1
- 9
1
vote
1 answer
Parse error in valid JSON data with nlohmann's C++ library
i have the following JSON data in a .json file:
[
{
"Type":"SET",
"routine":[
{
"ID":"1",
"InternalType":"Motorcycle",
"payload":"2"
},
{
"ID":"12",
…
schande
- 576
- 12
- 27
1
vote
2 answers
STD flexible data structure? c++
I'm using nlohmann json objects, since they can add key-value pairs after runtime (and can readily be serialized)... Though I realize this may sacrifice speed.
Are there any data structures, of similar flexibility, that are from standard c++…
user19816087
- 79
- 5
1
vote
1 answer
Why is this map returning an rvalue?
I am using the library nlohmann/json and wish to create an unordered_map of std::string to nlohmann::json.
#include
class basic_container {
public:
using key_type = std::string;
using mapped_type = nlohmann::json;
…
Jaan
- 330
- 2
- 9
1
vote
1 answer
Hidden friend to_json function unexpectedly resolves for shared_ptr
The code below (Goldbolt) compiles and runs (on both gcc and clang) and does what I would hope. But I'm surprised! I expected to have to use an adl_serializer specialisation (as opposed to the hidden friend here) for it to be able to find the…
tp288843
- 13
- 2