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70 lines
1.3 KiB
Markdown
70 lines
1.3 KiB
Markdown
# <small>nlohmann::json_pointer::</small>pop_front
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```cpp
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void pop_front();
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```
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Remove the first reference token.
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## Exception safety
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Strong exception safety: if an exception occurs, the original value stays intact.
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## Exceptions
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Throws [out_of_range.405](../../home/exceptions.md#jsonexceptionout_of_range405) if the JSON pointer has no parent.
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## Complexity
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Linear in the number of reference tokens in the `json_pointer`.
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## Examples
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??? example
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The example shows the usage of `pop_front`.
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```cpp
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#include <iostream>
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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int main()
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{
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// create empty JSON Pointer
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json::json_pointer ptr("/foo/bar/baz");
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std::cout << "\"" << ptr << "\"\n";
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// call pop_front()
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ptr.pop_front();
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std::cout << "\"" << ptr << "\"\n";
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ptr.pop_front();
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std::cout << "\"" << ptr << "\"\n";
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ptr.pop_front();
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std::cout << "\"" << ptr << "\"\n";
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}
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```
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Output:
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```json
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"/foo/bar/baz"
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"/bar/baz"
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"/baz"
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""
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```
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## See also
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- [front](front.md) return first reference token
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- [push_front](push_front.md) append an unescaped token at the start of the pointer
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## Version history
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- Added in version 3.13.0.
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