比较2个字符串并返回匹配字母java的数量

Question

How does one compare 2 Strings to return an int of amount matched in Java?

I have a "lottery number" which is a UUID and looks like 561637ba-06f6-4457-9787-ba65768c1b73 I would compare it to another string like 72c92628-5789-4d5c-9287-742dbc57cca9 which excluding the - would be 5 matching characters. would there be a faster way that just simply looping through every single character?

Answer 1

Assuming that both strings have the same length, this is as good as it gets:

public static int numberMatchingChars(String s1, String s2) {
    int count = 0;
    for (int i = 0; i < s1.length(); i++)
        if (s1.charAt(i) == s2.charAt(i) && s1.charAt(i) != '-')
            count++;
    return count;
}

Clearly, you'll have to iterate over each char on both strings.

Answer 2

Not sure if this would improve matters or not and assuming that both strings have the same length and format, but anyway, technically you do not need to visit every char.

String arr1[] = s1.split ("-");
String arr2[] = s2.split ("-");

int totCount = 0;

for (int x = 0; x < arr1.length; x++) {

   if (arr1[x].equals (arr2[x]) == false) {

       // compare char by char for arr1[x] to arr2[x]
       totCount += numberMatchingChars(arr1[x], arr2[x]);

   }
}

public static int numberMatchingChars(String s1, String s2) {
    int count = 0;
    for (int i = 0; i < s1.length(); i++)
        if (s1.charAt(i) == s2.charAt(i))
            count++;
    return count;
}