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◆ flatten()
template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
The function creates a JSON object whose keys are JSON pointers (see RFC 6901) and whose values are all primitive. The original JSON value can be restored using the unflatten() function.
- Returns
- an object that maps JSON pointers to primitive values
- Note
- Empty objects and arrays are flattened to
null and will not be reconstructed correctly by the unflatten() function.
- Complexity^^ Linear in the size the JSON value.
- Example^^ The following code shows how a JSON object is flattened to an
- object whose keys consist of JSON pointers. ^^
3 #include <nlohmann/json.hpp> 31 std::cout << std::setw(4) << j.flatten() << '\n'; basic_json<> json default JSON class
Output (play with this example online):^^ {
"/answer/everything": 42,
"/happy": true,
"/list/0": 1,
"/list/1": 0,
"/list/2": 2,
"/name": "Niels",
"/nothing": null,
"/object/currency": "USD",
"/object/value": 42.99,
"/pi": 3.141
}
^^ The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/flatten.cpp -o flatten
- See also
- unflatten() for the reverse function
- Since
- version 2.0.0
Definition at line 19700 of file json.hpp.
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