Comparing 2 lists together


#1

I’ve these 2 lists:

val forecast = listOf(30, 21, 29, 31, 40, 48, 53, 47, 37, 39, 31, 29)
val actual = listOf(27, 31, 27, 26, 21, 13, 21, 18, 33, 35, 40, 36)

And need to calculate the forecast error in each month, which is forecast-actual, so I tried the below:

var errors: MutableList<Double> = mutableListOf<Double>()

actual
      .forEachIndexed { index, d ->  forecast[index] - d}
      .let { i -> errors.add(i) }

But did not work, as the i resulted from forEachIndexed is a Unit not a Double :frowning:


#2
forecast.zip(actual){f,a -> f-a)