String Concatenation in Flutter with String Interpolation

String manipulation is a common task in programming, and it often involves concatenating variables or values into strings. Traditionally, this process could be cumbersome and error-prone, requiring multiple concatenation operations. However, Flutter offers a convenient feature called string interpolation that simplifies this task.

What is String Interpolation?

String interpolation is a technique that lets you include variables or expressions within strings without manually concatenating them. It improves code readability and reduces the risk of errors during string construction. Before we dive into string interpolation, let us have a look at the “old” approach.

Concatenating Strings using the “+” Operator

Before string interpolation was introduced, developers typically used the “+” operator to concatenate strings in Dart. Here is an example to demonstrate concatenation using the “+” operator:

String firstName = 'Tijn';
String lastName = 'van den Eijnde';
String fullName = 'My name is ' + firstName + ' ' + lastName;

In this code snippet, we have three variables: firstName, lastName, and fullName. We concatenate these variables using the “+” operator to construct the fullName string. The output will be:

My name is Tijn van den Eijnde

While concatenating strings with the “+” operator is a viable approach, it can become more tedious and error-prone when dealing with multiple variables or longer strings. Also you have to make sure that every variable is a String, otherwise it will throw an error. String interpolation provides a more concise and readable alternative.

String Interpolation in Flutter

In Flutter, the Dart programming language is used for development, and it provides support for string interpolation. Using string interpolation in Dart is straightforward. You can incorporate variables or expressions into strings by using the “$” symbol followed by the expression or variable you want to include. It does not matter if the string is in single '' or double "" quotes.

Let us dive into an example to illustrate how string interpolation works in Flutter:

String name = 'Tijn';
int age = 27;
String message = 'My name is $name and I am $age years old.';

In this code snippet, we have defined a variable name with the value “Tijn” and another variable age with the value 27. By using string interpolation, we construct the message string by embedding the name and age variables within it. The output of the print statement will be:

My name is Tijn and I am 27 years old.

As you can see, the values of the name and age variables are automatically substituted into the string, resulting in a compact and dynamic message.

String interpolation can also handle more complex expressions. Consider the following example:

int a = 10;
int b = 5;
String result = 'The sum of $a and $b is ${a + b}.';

In this case, we want to include the sum of variables a and b in the result string. By using curly braces {} around the expression a + b, we indicate that it should be evaluated as part of the string interpolation. The output will be:

The sum of 10 and 5 is 15.

By using string interpolation in Flutter, you can simplify string manipulation and make your code more compact and readable.

Benefits of String Interpolation

Using string interpolation in Flutter offers several benefits:

1. Code Readability: String interpolation improves code readability by allowing you to embed variables and expressions directly within the string, making it easier to understand the intended message.

2. Code Maintainability: With string interpolation, you do not need to manually concatenate variables and string literals using the “+” operator. This reduces the chance of introducing errors and simplifies future modifications to the string construction.

3. Efficiency: String interpolation provides a more efficient way to construct strings compared to manual concatenation. It reduces the number of operations required to build a string, resulting in improved performance.

4. Flexibility: String interpolation in Flutter allows you to incorporate complex expressions within strings, giving you the flexibility to create dynamic messages based on calculations or conditions.


String interpolation in Flutter makes string manipulation easier. It lets you create dynamic messages by combining variables or expressions with string literals. This feature improves code readability, makes maintenance simpler, and provides flexibility in string construction.

When working with Flutter and Dart, take advantage of string interpolation. If needed, you can still use the “+” operator to concatenate strings, but string interpolation offers a more convenient and straightforward implementation.

Tijn van den Eijnde
Tijn van den Eijnde
Articles: 87

Leave a Reply

Your email address will not be published. Required fields are marked *