I have a string that has three letters, 1, 2, X. Sometimes the string can be 12, or 1X, or 2X..etc.
I would like to append a "-" based on the position of the input letters. For example If I get 1, the result should be 1--, If I get X, the results should --X, If I get 2X, the result should be -2X.
My approach is to use a state machine of 2^n selections, but I'm looking for a smart apporach and better apporach.
More examples
Input 1 2 X 2X
Ouput 1-- -2- --X -2X
You can check if the input string contains the characters using String.contains():
String in = "12X";
String out;
out = in.contains("1") ? "1" : "-";
out += in.contains("2") ? "2" : "-";
out += in.contains("X") ? "X" : "-";
Which will produce your desired results:
(in) (out)
1 1--
12 12-
1X 1-X
X21 12X
X --X
As pointed out in the comments, this will be more efficient:
String in = "12X";
String out;
out = ( in.contains("1") ? "1" : "-" )
+ ( in.contains("2") ? "2" : "-" )
+ ( in.contains("X") ? "X" : "-" );
StringBuilder behind the scenes. Sure, for such a toy example it doesn't matter, but there's much to learning and upholding the right practices, so you hit the wall of insufficient resources only when the problem is intrinsically tough.This is one approach. Its advantage is that the size of code is constant with respect to the number of supported symbols.
final String x = "12X";
final char[] out = new char[x.length()];
Arrays.fill(out, '-');
for (int i = 0; i < input.length(); i++) {
final char c = input.charAt(i);
out[x.indexOf(c)] = c;
}
System.out.println(new String(out));
out[x.indexOf(c)] = c;, unless I am mistaken.
public static String getStringWithDashes(String input)
{
final char result[] = "---";
if (input.contains("1"))
{
result[0] == '1';
}
if (input.contains("2"))
{
result[1] == '2';
}
if (input.contains("X"))
{
result[2] == 'X';
}
return new String(result);
}
