# mapToDouble abstract method

DoubleStream mapToDouble(

1. double mapper(
   1. T
   )

)

Returns a DoubleStream consisting of the results of applying the given function to the elements of this stream.

## Example

    final prices = GenericStream.of(['10.5', '20.3', '15.7'])
        .mapToDouble((s) => double.parse(s));

## Implementation

    DoubleStream mapToDouble(double Function(T) mapper);