forked from Research/WhisperCom
Dominik Meyer
cc002ebfbb
git-subtree-dir: libs/json git-subtree-split: f42a74b8f53cc308647123d49d33d1c8122e3f42
1.0 KiB
1.0 KiB
basic_json::count
template<typename KeyT>
size_type count(KeyT&& key) const;
Returns the number of elements with key key
. If ObjectType
is the default std::map
type, the return value will
always be 0
(key
was not found) or 1
(key
was found).
Template parameters
KeyT
- A type for an object key.
Parameters
key
(in)- key value of the element to count.
Return value
Number of elements with key key
. If the JSON value is not an object, the return value will be 0
.
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 0
when executed on a JSON type that is not an object.
Example
??? example
The example shows how `count()` is used.
```cpp
--8<-- "examples/count.cpp"
```
Output:
```json
--8<-- "examples/count.output"
```
Version history
- Added in version 1.0.0.