Issue with java.lang.NumberFormatException

Question

I have a variable which contains some parameters which affect a created weka model. I want to change automatically the parameters values. I ve got the following:

String c [] ={"1.0", "10.0", "20.0", "30.0", "40.0", "50.0", "60.0","70.0", "80.0", 
"90.0","100.0", "200.0", "300.0", "400.0","500.0", "600.0", "700.0", "800.0", "1000.0",
"2000.0"};
    System.out.println(c[1]);
    String opt  = ("-C "+c[0] +"-L 0.001 -P 1.0E-12 -N 0 -V -1 -W 1 -K 
      weka.classifiers.functions.supportVector.PolyKernel -C 250007 -E 1.0 "); 

    String [] options = opt.split(" ");
    obj.train(new File(obj.str.get(2)), options);

I want to change inside the loop automatically the C parameter. However, when I wrote the below:

        String opt  = ("-C "+c[1] +"-L 0.001 -P 1.0E-12 -N 0 -V -1 -W 1 -K weka.classifiers.functions.supportVector.PolyKernel -C 250007 -E 1.0 "); 

I am receiving a java.lang.NumberFormatException: For input string. What I might have to do , to work proper? The error is in last line of the above code.

Answer 1

i give it a try:

String c [] ={"1.0", "10.0", "20.0", "30.0", "40.0", "50.0", "60.0","70.0", "80.0", "90.0","100.0", "200.0", "300.0", "400.0","500.0", "600.0", "700.0", "800.0", "1000.0", "2000.0"};
for (i = 0; i < c.length; i++){
    String opt  = String.format("-C %S 1.0 -L 0.001 -P 1.0E-12 -N 0 -V -1 -W 1 -K weka.classifiers.functions.supportVector.PolyKernel -C 250007 -E 1.0 ",c[i]); 
}

i used String.format("", ...) function and added %S as placeholder where the value of c[i] will be put into.