Programming in Dart: Fundamentals

So far in this part, you’ve saw a few ways to create a list.

The first way was to create what is known as a list literal. This is when we just used a couple of brackets to create an empty list. It’s convenient and you’ll be using it all the time.

The second way we created a list was to create an empty list using a constructor. We used this technique to create a list of potential null elements. Now, we are going to create a conditional list. Let’s say we just want to add test scores above a seventy five.

Well, we could create an empty list and then check each score. If it’s higher than seventy five, we could then add it. Dart actually provides a way of conditionally building a list when you are actually creating the list itself. Let’s see this in action.

We’re going to get started creating some grades. Open a new instance in Dartpad. Let’s create three grades.

var johnTest = 84;
var tedTest = 32;
var suzyTest = 80;

Now let’s create a list of tests.

var tests = [

];

Here we’ve defined the list literal. Now lets check each test while we build the list.

var tests = [
    if (johnTest > 75) johnTest,
    if (tedTest > 75) tedTest,
    if (suzyTest > 75) suzyTest
];

Finally, we’ll print out the list:

print(tests);

Now run the program. You’ll see that we have a list that contains John’s test and Suzy’s test while Ted’s test failed to make the grade.