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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>
add an object to an array Appends the given element value to the end of the JSON value. If the function is called on a JSON null value, an empty array is created before appending value.
- Parameters
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value | the value to add to the JSON array |
- Exceptions
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std::domain_error | when called on a type other than JSON array or null |
- Complexity
- Amortized constant.
- Example
- The example shows how
push_back and += can be used to add elements to a JSON array. Note how the null value was silently converted to a JSON array.
8 json array = {1, 2, 3, 4, 5};
12 std::cout << array << '\n';
13 std::cout << null << '\n';
22 std::cout << array << '\n';
23 std::cout << null << '\n';
a class to store JSON values Definition: json.hpp:130
namespace for Niels Lohmann Definition: json.hpp:55
void push_back(basic_json &&value) add an object to an array Definition: json.hpp:3615
Output (play with this example online): [1,2,3,4,5]
null
[1,2,3,4,5,6,7]
["first","second"]
The example code above can be translated withg++ -std=c++11 -Isrc doc/examples/push_back.cpp -o push_back
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