json/doc/mkdocs/docs/api/basic_json/find.md
Niels Lohmann 4703dd57e5
Merge branch 'develop' of https://github.com/nlohmann/json into string_view2
 Conflicts:
	doc/mkdocs/docs/api/basic_json/contains.md
	doc/mkdocs/docs/api/basic_json/find.md
	include/nlohmann/json.hpp
	single_include/nlohmann/json.hpp
	test/src/unit-regression2.cpp
2022-01-02 16:25:32 +01:00

66 lines
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Markdown

# <small>nlohmann::basic_json::</small>find
```cpp
template<typename KeyT>
iterator find(const KeyT& key);
template<typename KeyT>
const_iterator find(const KeyT& key) const;
```
Finds an element in a JSON object with key equivalent to `key`. If the element is not found or the JSON value is not an
object, `end()` is returned.
## Template parameters
`KeyT`
: A type for an object key that is less-than comparable with `string_t`. This can also be a string literal or a string
view (C++17).
## Parameters
`key` (in)
: key value of the element to search for.
## Return value
Iterator to an element with key equivalent to `key`. If no such element is found or the JSON value is not an object,
past-the-end (see `end()`) iterator is returned.
## Exception safety
Strong exception safety: if an exception occurs, the original value stays intact.
## Complexity
Logarithmic in the size of the JSON object.
## Notes
This method always returns `end()` when executed on a JSON type that is not an object.
## Examples
??? example
The example shows how `find()` is used.
```cpp
--8<-- "examples/find__key_type.cpp"
```
Output:
```json
--8<-- "examples/find__key_type.output"
```
## See also
- [contains](contains.md) checks whether a key exists
## Version history
- Added in version 1.0.0.
- Extended template `KeyT` in version 3.10.5 to also support `std::string_view`.