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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 = int64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator>
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(std::initializer_list<basic_json>, 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.
- Example
- The following code shows an example for the array function.
14 std::cout << j_no_init_list << '\n';
15 std::cout << j_empty_init_list << '\n';
16 std::cout << j_nonempty_init_list << '\n';
17 std::cout << j_list_of_pairs << '\n';
static basic_json array(std::initializer_list< basic_json > init=std::initializer_list< basic_json >()) explicitly create an array from an initializer list Definition: json.hpp:1295
a class to store JSON values Definition: json.hpp:130
namespace for Niels Lohmann Definition: json.hpp:55
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 -Isrc doc/examples/array.cpp -o array
- See also
- basic_json(std::initializer_list<basic_json>, bool, value_t) - create a JSON value from an initializer list
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basic_json object(std::initializer_list<basic_json>) - create a JSON object value from an initializer list
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