:title
map

:sig
StringList map(StringList items, function<String (String)> f)
vector<R> map(vector<T> items, function<R (T)> f)

:params
items : list of items to transform
f : a function that returns the transformed value for each item
return value : a new list containing the transformed values

:see
>string
filter
StringList
0_DValue

:content
Returns a new list by calling `f` for each item in `items`.

```cpp
auto upper = map(names, [](String s) { return(to_upper(s)); });
```

Use `filter()` when you want to keep only matching items, and `map()` when you want to transform each item.

## Related Concepts

- JavaScript / React: `Array.prototype.map()`
- PHP: `array_map()`
