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◆ array()
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';
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 16089 of file json.hpp.
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