Parsing Individual Members

Parsing single members from the JSON data is common. This can be to discriminate on a single member or when only a single member is needed.

{
  "member0": 55,
  "member1": [
    1,
    2,
    3,
    4,
    5
  ],
  "member2": {
    "a": 123.4,
    "b": "found me"
  }
}

With the previous JSON data, the next example will extract the member "a.b", the "b" member of the "a" member of the root object.

To see a working example using this code, refer to cookbook_parsing_individual_members1_test.cpp.

std::string b_value = daw::json::from_json<std::string>( json_data, "a.b" );

b_value should have a value of "found me"

Below shows when member is known to be an array and full control of the resulting collection is needed.

Too see a working example using this code, refer to cookbook_parsing_individual_members2_test.cpp.

std::vector<int> values = daw::json::from_json_array<int>( json_data, "member1" );

Specifying array indexes

In the member path array indexes are specified inside square brackets [ and ]. Below the 3rd item of "member1" will be extracted

Too see a working example using this code, refer to cookbook_parsing_individual_members3_test.cpp.

int third_value = daw::json::from_json<int>( json_data, "member1[2]" );