Dart – Interesting facts about String Interpolation
In this post, we will learn a few interesting things about String interpolation in Dart.
1. Syntax:
The value of an expression can be placed inside a string using:
${expression}
final coflutter = 'Coflutter';
print('Hello ${coflutter}. Your name has ${coflutter.length} characters.');
// Hello Coflutter. Your name has 9 characters.
2. If the expression is a single identifier (variable), the brackets ({ }) can be omitted.
final coflutter = 'Coflutter';
print('Goodbye $coflutter.');
// Goodbye Coflutter.
3. if..else inside the bracket
I don’t recommend this because it will make your code more difficult to read, but here I just show you what the language can do.
final password = 'password';
print('The password is ${password.length > 8 ? 'OK' : 'weak'}!');
// The password is weak!
4. Complex expression inside the brackets
final password = 'password';
print('Password length is: ${((String pwd) {
return pwd.length;
})(password)}.');
// Password length is: 8.
5. Object
If an object is placed inside the brackets, Dart internally calls toString() on that object. So that you don’t need to call toString() yourself.
(I also wrote a blog about How to print an object in Dart here).
class Student {
final String name;
final int age;
Student(this.name, this.age);
@override
String toString() {
return 'Student: {name: ${name}, age: ${age}}';
}
}
final student = Student('Coflutter', 30);
print('Info: $student');
// Info: Student: {name: Coflutter, age: 30}
Happy coding! And please don’t hesitate to add your comments!
The original post is here. You can find other posts about Dart/Fluter on my Coflutter blog.
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