Collections.max(arraylist) doesn't work, and a regular for loop won't work either.
What I have is:
ArrayList<Forecast> forecasts = current.getForecasts();
Collections.max(forecast) gives me this error:
The method max(Collection<? extends T>) in the type Collections is
not applicable for the arguments (ArrayList<Forecast>)
The ArrayList holds Forecast objects which each has an int field for the temperature of each day. I am trying to store the max in an int max.
As your ArrayList contains Forecast objects you'll need to define how the max method should find the maximum element within your ArrayList.
something along the lines of this should work:
ArrayList<Forecast> forecasts = new ArrayList<>();
// Forecast object which has highest temperature
Forecast element = Collections.max(forecasts, Comparator.comparingInt(Forecast::getTemperature));
// retrieve the maximum temperature
int maxTemperature = element.getTemperature();
Streams are perfect for these sort of problems.
Forecast highest = forecasts.stream()
.max((fc1, fc2) -> fc1.getTemp() - fc2.getTemp())
.get();
Another solution is use map reduce:
Optional<Forecast> element = forecasts
.stream()
.reduce((a,b) -> a.getTemperature() > b.getTemperature() ? a : b );
In this way you could even use use parallelStream()
here is the simple method that return a max value from arraylist
public static object GetMaxValue(ArrayList arrayList)
{
ArrayList sortArrayList= arrayList;
sortArrayList.Sort();
sortArrayList.Reverse();
return sortArrayList[0];
}
I have two ideas. First of all, you used forecast in the parameter, but it should be forecasts. Also, you never gave your code for the class Forecast. I may be wrong, because I didn't see all of your code, but you need to convert Forecast to a Integer. Do this by Integer i = Integer.parseInt(forecasts); Next use Collections.max(i)
forecastsArrayList of Forecast, is not an array of int. Both a loop andmax()work correctly when used appropriately.