How to sum only those objects of the array that require the status (true)

October 18, 2022

I have an array with such data (more data in reality)

         [ 
           {
                 serviceid: "979cf8e6",
                 amount: 1,
                 price: 11,
                 materialsPrice: 100,
                 enable: true,
                 chenge: true
            },
            {
                 serviceid: "979cf812",
                 amount: 1,
                 price: 15.5,
                 materialsPrice: 0,
                 enable: true,
                 chenge: true
            }
         ]

I want to match all "price" in an array in which change = true. Now I’m using this query for this.

   double get sumPay {
    double sum = listVariant
        .map((e) => e.price )
        .fold(0, (previousValue, price) => previousValue + price!);
    return sum;
  }

But this request sums up all the elements, and it will give me only those in which the status is change: true. I will be grateful for your help)

>Solution :

Try this

   double get sumPay {
    var changeList = listVariant.where((e) => e.change == true);
    double sum = changeList
        .fold(0, (previous, next) => previous.price + next.price);
    return sum;
  }