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### jsoncons::jsonpointer::flatten
```cpp
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
template <typename Json>
Json flatten(const Json& value); (1)
template <typename Json>
Json unflatten(const Json& value, unflatten_options options = unflatten_options::none); (2) (since 0.150.0)
```
(1) flattens a json object or array into a single depth object of JSON Pointer-value pairs.
- The keys in the flattened object are JSONPointer's.
- (until 0.160.0) The values are primitive (string, number, boolean, or null). Empty objects or arrays become null.
- (since 0.160.0) The values can be string, number, boolean, null, empty object (`{}`) or empty array (`[]`).
(2) unflattens a json object of JSON Pointer-value pairs. There is no unique solution,
an integer appearing in a path could be an array index or it could be an object key.
The default is to attempt to preserve arrays. [unflatten_options](unflatten_options.md)
provides additonal options.
#### Return value
(1) A flattened json object of JSON Pointer-value pairs
(2) An unflattened json object
### Examples
#### Flatten and unflatten a json object with non-numeric keys
```cpp
#include <jsoncons/json.hpp>
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
// for brevity
using jsoncons::json;
namespace jsonpointer = jsoncons::jsonpointer;
int main()
{
json input = json::parse(R"(
{
"application": "hiking",
"reputons": [
{
"rater": "HikingAsylum",
"assertion": "advanced",
"rated": "Marilyn C",
"rating": 0.90
},
{
"rater": "HikingAsylum",
"assertion": "intermediate",
"rated": "Hongmin",
"rating": 0.75
}
]
}
)");
json flattened = jsonpointer::flatten(input);
std::cout << pretty_print(flattened) << "\n\n";
json unflattened = jsonpointer::unflatten(flattened);
assert(unflattened == input);
}
```
Output:
```
{
"/application": "hiking",
"/reputons/0/assertion": "advanced",
"/reputons/0/rated": "Marilyn C",
"/reputons/0/rater": "HikingAsylum",
"/reputons/0/rating": 0.9,
"/reputons/1/assertion": "intermediate",
"/reputons/1/rated": "Hongmin",
"/reputons/1/rater": "HikingAsylum",
"/reputons/1/rating": 0.75
}
```
#### Flatten and unflatten a json object with numberlike keys
```cpp
int main()
{
json input = json::parse(R"(
{
"discards": {
"1000": "Record does not exist",
"1004": "Queue limit exceeded",
"1010": "Discarding timed-out partial msg"
},
"warnings": {
"0": "Phone number missing country code",
"1": "State code missing",
"2": "Zip code missing"
}
}
)");
json flattened = jsonpointer::flatten(input);
std::cout << "(1)\n" << pretty_print(flattened) << "\n";
json unflattened1 = jsonpointer::unflatten(flattened);
std::cout << "(2)\n" << pretty_print(unflattened1) << "\n";
json unflattened2 = jsonpointer::unflatten(flattened,
jsonpointer::unflatten_options::assume_object);
std::cout << "(3)\n" << pretty_print(unflattened2) << "\n";
}
```
Output:
```
(1)
{
"/discards/1000": "Record does not exist",
"/discards/1004": "Queue limit exceeded",
"/discards/1010": "Discarding timed-out partial msg",
"/warnings/0": "Phone number missing country code",
"/warnings/1": "State code missing",
"/warnings/2": "Zip code missing"
}
(2)
{
"discards": {
"1000": "Record does not exist",
"1004": "Queue limit exceeded",
"1010": "Discarding timed-out partial msg"
},
"warnings": ["Phone number missing country code", "State code missing", "Zip code missing"]
}
(3)
{
"discards": {
"1000": "Record does not exist",
"1004": "Queue limit exceeded",
"1010": "Discarding timed-out partial msg"
},
"warnings": {
"0": "Phone number missing country code",
"1": "State code missing",
"2": "Zip code missing"
}
}
```
### See also
[jsoncons::jsonpath::flatten](../jsonpath/flatten.md)
|
