java - Insert several chars instead of one into string -

i have string expression. example string "a + b". need insert float variables instead of characters. "a" = 2.4494 , "b" = 5.545466. convert variables string , make strings expression , values char arrays.

expr = expressions.get(i)[0]; // string expression         (int j = 0; j < valslistarray.length; j++) {//find characters , values                                                         //they should have                   string selection = (string) valslistarray[j].getselecteditem(); //get                                                                 //chosen character             float valuefloat = segmentareas.get(j);          //get value             string valuestring = "" + valuefloat;             char[] charexpr = expr.tochararray();                           //             char[] valuechar = valuestring.tochararray();             char[] ch = selection.tochararray();             (int jj = 0; jj < charexpr.length; jj++) {                 if (charexpr[jj] == ch[0]) {                       charexpr[jj] = valuechar[0];    //here problem                 }             }             string s =new string(charexpr);             expr = s; 

but cant understand how insert whole chararray instead 1 character...

for inserting several chars in array @ once, consider using stringbuilder instead. here's how you'd use it:

stringbuilder sb = new stringbuilder("initial string"); sb.append("another string"); sb.append(new char[] {'c', 'h', 'a', 'r', 's'}); sb.append(1.0f); string str = sb.tostring();