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◆ array()
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>
Creates a JSON array value from a given initializer list. That is, given a list of values a, b, c , creates the JSON value [a, b, c] . If the initializer list is empty, the empty array [] is created.
- Note
- This function is only needed to express two edge cases that cannot be realized with the initializer list constructor (basic_json(initializer_list_t, bool, value_t)). These cases are:
- creating an array whose elements are all pairs whose first element is a string – in this case, the initializer list constructor would create an object, taking the first elements as keys
- creating an empty array – passing the empty initializer list to the initializer list constructor yields an empty object
- Parameters
-
[in] | init | initializer list with JSON values to create an array from (optional) |
- Returns
- JSON array value
- Complexity^^ Linear in the size of init.
- Exception safety^^ Strong guarantee: if an exception is thrown, there are no
- changes to any JSON value.
- Example^^ The following code shows an example for the array
- function. ^^
2 #include <nlohmann/json.hpp> 15 std::cout << j_no_init_list << '\n'; 16 std::cout << j_empty_init_list << '\n'; 17 std::cout << j_nonempty_init_list << '\n'; 18 std::cout << j_list_of_pairs << '\n'; static basic_json array(initializer_list_t init={}) explicitly create an array from an initializer list
basic_json<> json default JSON class
Output (play with this example online):^^ []
[]
[1,2,3,4]
[["one",1],["two",2]]
^^ The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/array.cpp -o array
- See also
- basic_json(initializer_list_t, bool, value_t) – create a JSON value from an initializer list
-
object(initializer_list_t) – create a JSON object value from an initializer list
- Since
- version 1.0.0
Definition at line 13877 of file json.hpp.
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