# <small>nlohmann::basic_json::</small>begin

```cpp
iterator begin() noexcept;
const_iterator begin() const noexcept;
```

Returns an iterator to the first element.

![Illustration from cppreference.com](../../images/range-begin-end.svg)

## Return value

iterator to the first element

## Exception safety

No-throw guarantee: this member function never throws exceptions.

## Complexity

Constant.

## Examples

??? example

    The following code shows an example for `begin()`.
    
    ```cpp
    #include <iostream>
    #include <nlohmann/json.hpp>
    
    using json = nlohmann::json;
    
    int main()
    {
        // create an array value
        json array = {1, 2, 3, 4, 5};
    
        // get an iterator to the first element
        json::iterator it = array.begin();
    
        // serialize the element that the iterator points to
        std::cout << *it << '\n';
    }
    
    ```
    
    Output:
    
    ```json
    1
    
    ```

## See also

- [end](end.md) returns an iterator to one past the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [items](items.md) returns an iteration proxy to access keys and values during range-based for loops
- [Iterators](../../features/iterators.md) - the article on iterators

## Version history

- Added in version 1.0.0.