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
2
votes
0 answers
How to convert nlohmann binary to uint8_t vector?
I get a msgpack object, wrapping an array with uint8_t values from an API and load it to the nlohmann/json library with json::from_msgpack, when I print the json document I get this:
{
"raw_data": {
"bytes": [4, 3, 2, 0, 0, 116, 68],
…
Paul Würtz
- 1,641
- 3
- 22
- 35
2
votes
0 answers
How to pretty print nlohmann::json json file? C++
How can I pretty print my nlohmann::json json file?
I have tried o << std::setw(4) << data << std::endl; like an old stackoverflow question said to do, but I get an error saying:
main.cpp:39:32: error: no member named 'setw' in namespace 'std'
o <<…
JohnJameson
- 81
- 1
- 12
2
votes
1 answer
How to write a vector of structs to json file?
Basically, this question is inverse to this one.
I want to write a vector of structs
struct Test {
std::string Name;
std::string Val;
};
into a file:
[
{
"Name": "test",
"Val": "test_val"
},
{
"Name": "test2",
"Val":…
Ronaldinho
- 375
- 1
- 12
2
votes
1 answer
How can I `nlohmann::json::get>`?
I've defined the following serializer stack:
namespace discordpp {
using Snowflake = uint64_t;
}
namespace nlohmann {
template <> struct adl_serializer {
static void to_json(json &j, const discordpp::Snowflake sf) {
…
Aido
- 1,524
- 3
- 18
- 41
2
votes
1 answer
Is there a way to serialize a heterogenous vector with nlohmann_json lib?
Hi Stack Overflow Community !
I am working on a project that heavily uses the interesting nlohmann_json library and it appears that I need to add an inheritance link on a specific class, which objects are serialized at one moment.
I tried different…
mscherer
- 97
- 1
- 3
- 12
2
votes
2 answers
nlohmann and copying maps
Anyone has idea how to quickly copy nlohmann::json MAP values to an other nlohmann::json?
nlohmann::json j1;
nlohmann::json j2;
j1["MAP"]["value1"] = 1;
j2["MAP"]["value2"] = 2;
j2["MAP"] += j1["MAP"];
This will throw because += will think that I…
Grzegorz
- 3,207
- 3
- 20
- 43
2
votes
1 answer
Error in converting from json using nlohmann json package
I'm trying to convert the json of the form
{
"content": {
"test_key": "test"
},
"sender": "alice",
"type": "key_type"
}
to my object which is
template
struct Event
{
Content content;
std::string…
Bad_Panda
- 427
- 1
- 5
- 11
2
votes
0 answers
How to merge patch multiple level json with nlohmann library
I have a list of paths like:"blabla/bleble/blibli", "blabla/blibli/bleble"
I've succeeded to transform one to this: {"blabla":{"bleble":{"blibli":null}}} with this function:
nlohmann::json transform(std::pair aaa){
…
Martin Dubois
- 23
- 6
2
votes
1 answer
How to merge same key json data into one in c++ using nlhoman json
I have below JSON data:
{
"Created": "2019-08-01T14:36:49Z",
"Tags": [
{
"ObjectId": "1",
"Time": 6,
"TrackerId": "W1"
},
{
"ObjectId": "2",
"Time": 4,
…
S Andrew
- 5,592
- 27
- 115
- 237
2
votes
2 answers
C++ : using nlohmann json in project
I am trying to use nlohmann json in my C++ project. I extracted the zipped file after I downloaded it from github. I renamed the extracted folder to be nlohmann_json and just copied it inside my project .
The github doc says :
json.hpp is the…
Istiaque Ahmed
- 6,072
- 24
- 75
- 141
2
votes
1 answer
Why is json file deleting old inputs from c++?
I need to make a program that stores usernames and passwords. I want to store them in json file. I already made a program that kinda does that, but it deletes old inputs and rewrite them as new.
int main()
{
char pass[12];
char…
Reinis Zīverts
- 43
- 5
2
votes
0 answers
nlohmann json ambiguous overload for 'operator='
I'm getting this compilation error with the following code
#include
#include
#include "nlohmann_json.hpp"
namespace nlohmann {
template
struct adl_serializer> {
static void…
SU3
- 5,064
- 3
- 35
- 66
2
votes
1 answer
Using valijson with Nlohmann's JSON for Modern C++ to validate schemas with subschemas
Can valijson be made to work with Nlohmann's json parser for schemas read from a file with references to subschemas in other files?
json mySchemaDoc;
if (!valijson::utils::loadDocument("testSchema.json", mySchemaDoc)) {
cout << "failed to create…
Jimmy Joe
- 121
- 8
2
votes
1 answer
C++ nlohmann/json how to use runtime provided json_pointers to read json values
I am using the json parser Json for Modern C++ (https://github.com/nlohmann/json). I know that I can get the value of a JSON value with a JSON_Pointer:
auto v1 = j["/a/b/c"_json_pointer];
But how would I go about getting the value if the JSON…
Ronald Currier
- 575
- 1
- 5
- 11
1
vote
1 answer
Store std::optional value to json file c++
I have a std::optional test;
I want to store this value to json file, and since it is optional, I donot know until runtime, if the variable has a value or not. So I am trying to do this
frameJson["Test"] = test.has_value() ? test.value() :…
Nitron_707
- 307
- 4
- 10