Fake Binary

public class FakeBinary {
    public static String fakeBin(String numberString) {
        return numberString.replaceAll("[0-4]", "0").replaceAll("[5-9]", "1");
    }
}

import java.util.Arrays;
import java.util.stream.Collectors;

public class FakeBinary {
  public static String fakeBin(String numberString) {
        if (numberString == null || numberString.length() == 0) return "";
        return Arrays.stream(numberString.split("")).map(s -> {return Integer.parseInt(s) < 5 ? "0" : "1";}).collect(Collectors.joining());
    }
}

public class FakeBinary {
    public static String fakeBin(String s) {
        return s.replaceAll("[1-4]","0").replaceAll("[^0]","1");
    }
}

import static java.util.stream.Collectors.joining;

public class FakeBinary {
    public static String fakeBin(String str) {
        return str.chars().mapToObj(c -> c < '5' ? "0" : "1").collect(joining());
    }
}

import java.util.stream.Collectors;

public class FakeBinary {
    public static String fakeBin(String numberString) {
        return numberString.chars()
            .mapToObj(x -> String.valueOf((Character.getNumericValue(x) < 5) ? 0 : 1))
            .collect(Collectors.joining());
    }
}

function fake_bin(string $s): string {
  return preg_replace(array('/[0-4]/', '/[5-9]/'), array('0', '1'), $s);
}

function fake_bin(string $s): string {
  return strtr($s, '0123456789', '0000011111');
}

function fake_bin(string $s): string {
  $s = str_replace(range(0,4), 0, $s);
  $s = str_replace(range(5,9), 1, $s);
  
  return $s;
}

function fake_bin(string $s): string {
  $result = "";
  foreach (str_split($s) as $char)
    if ((int)$char < 5) 
      $result = $result . '0';
    else
      $result = $result . '1';    
  return $result;
}