Question

我需要输入两个字符串，第一个字符串是任意字，第二个字符串是前一个字符串的一部分，我需要输出第二个字符串出现的次数。例如：String 1 = CATSATONTHEMAT String 2 = AT。输出为3，因为AT在CATSATONTHEMAT中出现三次。这是我的代码：

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    String word8 = sc.next();
    String word9 = sc.next();
    int occurences = word8.indexOf(word9);
    System.out.println(occurences);
}

当我使用此代码时，它会输出1。

Answer 1

有趣的解决方案：

public static int countOccurrences(String main, String sub) {
    return (main.length() - main.replace(sub, "").length()) / sub.length();
}

基本上我们在这里做的是从main中删除sub的所有实例所得的字符串长度减去main的长度 - 然后我们将此数字除以sub的长度，用于确定删除了sub的出现次数，并给出了答案。

所以最后你会得到这样的东西：

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    String word8 = sc.next();
    String word9 = sc.next();
    int occurrences = countOccurrences(word8, word9);
    System.out.println(occurrences);

    sc.close();
}

Answer 2

您也可以尝试：

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    String word8 = sc.nextLine();
    String word9 = sc.nextLine();
    int index = word8.indexOf(word9);
    sc.close();
    int occurrences = 0;
    while (index != -1) {
        occurrences++;
        word8 = word8.substring(index + 1);
        index = word8.indexOf(word9);
    }
    System.out.println("No of " + word9 + " in the input is : " + occurrences);
}

Answer 3

为什么没有人发布最明显，最快速的解决方案？

int occurrences(String str, String substr) {
    int occurrences = 0;
    int index = str.indexOf(substr);
    while (index != -1) {
        occurrences++;
        index = str.indexOf(substr, index + 1);
    }
    return occurrences;
}

Answer 4

另一种选择：

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    String word8 = sc.next();
    String word9 = sc.next();
    int occurences = word8.split(word9).length;
    if (word8.startsWith(word9)) occurences++;
    if (word8.endsWith(word9)) occurences++;
    System.out.println(occurences);

    sc.close();
}

startsWith和endsWith是必需的，因为split()省略了尾随空字符串。

获取另一个字符串中一个字符串的出现次数

4 个答案: