String str = "Hafce00453dfg23.4fdksd"; double newdbl = double.parse(str.replaceAll(RegExp(r'[^0-9.]'),'')); print(newdbl);// output: 45323.4// String -> double main () { var onePointOne = double.parse('1.1'); print(onePointOne == 1.1); // prints true } var myInt = int.parse('12345'); assert(myInt is int); print(myInt); // 12345