Data Pipeline Patterns

Reduce Total

Reduction carries one accumulator through every input value.

Program

Play the program to sum amounts and optionally add shipping.

reduce_total.dart 
void main() {
  var amounts = [12, 8, 15];
  var includeShipping = ;
  var total = 0;
  for (var amount in amounts) {
    total += amount;
  }
  if (includeShipping) total += 5;
  print('total=$total');
}

void main() {
  var amounts = [12, 8, 15];
  var includeShipping = ;
  var total = 0;
  for (var amount in amounts) {
    total += amount;
  }
  if (includeShipping) total += 5;
  print('total=$total');
}
accumulator `total` stores the running result.
compound assignment `total += amount` adds into the accumulator.
optional stage The shipping branch is another small pipeline stage.