String to Double in Dart

In Dart, converting a string to a double is fairly simple using the double.parse() method. This method takes a string as an argument and returns a double.

Syntax:

double double.parse(String source, [double onError(String source)])

The source parameter is the string that needs to be converted to a double. The onError parameter is optional and it is a callback function that is called when an error occurs during the conversion process.

Example:

void main() {
  String str = '3.14';
  double pi = double.parse(str);
  print('The value of pi is $pi');
}

Output:

The value of pi is 3.14

If the string passed as an argument is not a valid double, an error will be thrown. So, it's always a good practice to use try-catch when parsing a string to double.

void main() {
  String str = 'hello';
  try {
    double number = double.parse(str);
    print('The value of number is $number');
  } catch (e) {
    print('Cannot convert string to double: $e');
  }
}

Output:

Cannot convert string to double: FormatException: Invalid double

Conclusion:

Converting a string to double in Dart is easy and can be done using the double.parse() method. Always remember to use try-catch when parsing a string to double to avoid errors.