# nlohmann::json_pointer::pop_back

```
void pop_back();
```

Remove the last reference token.

## Exception safety

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

## Exceptions

Throws [out_of_range.405](https://json.nlohmann.me/home/exceptions/#jsonexceptionout_of_range405) if the JSON pointer has no parent.

## Complexity

Constant.

## Examples

Example

The example shows the usage of `pop_back`.

```
#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_back()
    ptr.pop_back();
    std::cout << "\"" << ptr << "\"\n";

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

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

Output:

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

## See also

- [back](https://json.nlohmann.me/api/json_pointer/back/index.md) return last reference token
- [push_back](https://json.nlohmann.me/api/json_pointer/push_back/index.md) append an unescaped token at the end of the pointer
- [parent_pointer](https://json.nlohmann.me/api/json_pointer/parent_pointer/index.md) returns the parent of this JSON pointer

## Version history

Added in version 3.6.0.