java替换字符串特定索引中的子字符串

Question

如何使用“将最后一个子字符串 10 替换为 01”算法将字符串 10100 替换为 10010。我试过了

s=s.replace(s.substring(a,a+2), "01");

但这会返回 01010，同时替换 “10” 的第一个和第二个子字符串。"a"代表 s.lastindexOf("10");

Answer 1

这是您可以使用的一个简单且可扩展的函数。首先是它的使用/输出，然后是它的代码。

String original  = "10100";
String toFind    = "10";
String toReplace = "01";
int ocurrence    = 2;
String replaced  = replaceNthOcurrence(original, toFind, toReplace, ocurrence);
System.out.println(replaced); // Output: "10010"

original  = "This and This and This";
toFind    = "This";
toReplace = "That";
ocurrence = 3;
replaced  = replaceNthOcurrence(original, toFind, toReplace, ocurrence);
System.out.println(replaced); // Output: "This and This and That"

函数代码:

public static String replaceNthOcurrence(String str, String toFind, String toReplace, int ocurrence) {
    Pattern p = Pattern.compile(Pattern.quote(toFind));
    Matcher m = p.matcher(str);
    StringBuffer sb = new StringBuffer(str);
    int i = 0;
    while (m.find()) {
        if (++i == ocurrence) { sb.replace(m.start(), m.end(), toReplace); break; }
    }
    return sb.toString();
}