|
◆ unflatten()
basic_json nlohmann::basic_json::unflatten |
( |
| ) |
const |
|
inline |
The function restores the arbitrary nesting of a JSON value that has been flattened before using the flatten() function. The JSON value must meet certain constraints:
- The value must be an object.
- The keys must be JSON pointers (see RFC 6901)
- The mapped values must be primitive JSON types.
- Returns
- the original JSON from a flattened version
- Note
- Empty objects and arrays are flattened by flatten() to
null values and can not unflattened to their original type. Apart from this example, for a JSON value j , the following is always true: j == j.flatten().unflatten() .
- Complexity
- Linear in the size the JSON value.
- Exceptions
-
type_error.314 | if value is not an object |
type_error.315 | if object values are not primitive |
- Example
- The following code shows how a flattened JSON object is unflattened into the original nested JSON object.
3 #include <nlohmann/json.hpp>
12 { "/answer/everything", 42},
18 { "/nothing", nullptr},
19 { "/object/currency", "USD"},
20 { "/object/value", 42.99},
25 std::cout << std::setw(4) << j_flattened.unflatten() << '\n';
Output (play with this example online): {
"answer": {
"everything": 42
},
"happy": true,
"list": [
1,
0,
2
],
"name": "Niels",
"nothing": null,
"object": {
"currency": "USD",
"value": 42.99
},
"pi": 3.141
}
The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/unflatten.cpp -o unflatten
- See also
- flatten() for the reverse function
- Since
- version 2.0.0
Definition at line 22059 of file json.hpp.
|