json/api/json_pointer/pop_front.md

nlohmann::json_pointer::pop_front

void pop_front();

Remove the first reference token.

Exception safety

Strong exception safety: if an exception occurs, the original value stays intact.

Exceptions

Throws out_of_range.405 if the JSON pointer has no parent.

Complexity

Linear in the number of reference tokens in the json_pointer.

Examples

??? example

The example shows the usage of `pop_front`.
 
```cpp
#include <iostream>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

int main()
{
    // create empty JSON Pointer
    json::json_pointer ptr("/foo/bar/baz");
    std::cout << "\"" << ptr << "\"\n";

    // call pop_front()
    ptr.pop_front();
    std::cout << "\"" << ptr << "\"\n";

    ptr.pop_front();
    std::cout << "\"" << ptr << "\"\n";

    ptr.pop_front();
    std::cout << "\"" << ptr << "\"\n";
}

```

Output:

```json
"/foo/bar/baz"
"/bar/baz"
"/baz"
""

```

See also

• front return first reference token
• push_front append an unescaped token at the start of the pointer

Version history

• Added in version 3.13.0.