字符串练习

按指定格式拼接字符串

定义一个方法，把数组{1,2,3]按照指定格式拼接成一个字符串。格式参照如下:[ word1#word2#word3]。

    public static void main(String[] args) {
        int[] arr = {1,2,3};
        System.out.println(FromArray(arr));
    }
    public static String FromArray(int[] arr){
        String str = "[";
        for (int i = 0; i < arr.length; i++) {
            if (i == arr.length-1){
                str+= "word"+arr[i]+"]";
            }else {
                str+= "word"+arr[i]+"*";
            }
        }
        return str;
    }

运行结果：

 

 

 

 

键盘输入一个字符串,并且统计其中各种字符出现的次数。

种类有:大写字母、小写字母、数字、其他

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入一个字符串");
        String input = sc.next();
        int countUpper = 0;
        int countLower = 0;
        int countNumber = 0;
        int countAuthor = 0;
        char[] chars = input.toCharArray();
        for (int i = 0; i < chars.length; i++) {
            char ch = chars[i];
            if ('A' <= ch && ch <= 'Z'){
                countUpper++;
            }else if ('a' <= ch && ch <= 'z'){
                countLower++;
            }else if ('0' <= ch && ch <= '9'){
                countNumber++;
            }else {
                countAuthor++;
            }
        }
        System.out.println("大写字母："+countUpper);
        System.out.println("小写字母："+countLower);
        System.out.println("数字："+countNumber);
        System.out.println("其他："+countAuthor);
    }

运行结果：