Switch Statements

Learn how to use switch statements for multi-way branching in Dart

Overview

Switch statements provide a clean way to handle multiple conditions based on the value of an expression. They are particularly useful when you need to compare a single value against multiple possible matches.

Basic Syntax

switch (expression) {
  case value1:
    // Code to execute
    break;
  case value2:
    // Code to execute
    break;
  default:
    // Code to execute if no case matches
}

Each case must end with break, continue, return, or throw. Otherwise, execution will fall through to the next case.

String Matching Example

Switch statements work well with strings:

void main() {
  String dia = 'sábado';

  switch (dia) {
    case 'lunes':
      print('Inicio de Semana');
      break;
    case 'sábado':
      break;
    case 'viernes':
      print('Casi es fin de semana');
      break;
    case 'domingo':
      print('Fin de Semana');
      break;
    default:
      print('Día inválido!');
  }
}

Integer Matching Example

Switch statements can also match integer values:

int calificacion = 8;

switch (calificacion) {
  case 6:
    print('Suficiente');
    break;
  case 7:
    print('Bueno');
    break;
  case 8:
    print('Muy Bueno');
    break;
  case 9:
    print('Sobresaliente');
    break;
  case 10:
    print('Excelente');
    break;
  default:
    print('No Suficiente');
}
// Output: Muy Bueno

Pattern Matching (Dart 3.0+)

Dart 3.0 introduced enhanced pattern matching in switch statements, allowing for more complex conditions.

int calificacion = 0;

switch (calificacion) {
  case >= 0 && <= 5:
    print('No Suficiente');
    break;
  case 6:
    print('Suficiente');
    break;
  case 7:
    print('Bueno');
    break;
  case 8:
    print('Muy Bueno');
    break;
  case 9:
    print('Sobresaliente');
    break;
  case 10:
    print('Excelente');
    break;
}

Complete Example

void main() {
  String dia = 'sábado';

  switch (dia) {
    case 'lunes':
      print('Inicio de Semana');
      break;
    case 'sábado':
      break;
    case 'viernes':
      print('Casi es fin de semana');
      break;
    case 'domingo':
      print('Fin de Semana');
      break;
    default:
      print('Día inválido!');
  }

  int calificacion = 0;
  switch (calificacion) {
    case >= 0 && <= 5:
      print('No Suficiente');
      break;
    case 6:
      print('Suficiente');
      break;
    case 7:
      print('Bueno');
      break;
    case 8:
      print('Muy Bueno');
      break;
    case 9:
      print('Sobresaliente');
      break;
    case 10:
      print('Excelente');
      break;
  }
}

When to Use Switch vs If-Else

1. Use switch for discrete values

   Switch statements are ideal when checking a single variable against multiple specific values.

2. Use if-else for ranges

   If-else statements are better for complex conditions or range checks (though Dart 3.0+ supports patterns in switch).

3. Consider readability

   Choose the option that makes your code most readable for the specific use case.

Important Notes

Every case in a switch statement must have a terminating statement (break, continue, return, or throw). Empty cases can fall through to the next case.

Supported Types

Switch statements in Dart work with:

• Integers
• Strings
• Enums
• Compile-time constants
• Objects (with proper equality implementation)

Default Case

The default case is optional but recommended. It handles any value that doesn’t match the specified cases:

switch (value) {
  case 'expected':
    print('Matched!');
    break;
  default:
    print('No match found');
}