java如何计算字符串中的大小写字母？

Question

哟，所以我试图制作一个程序，可以从用户那里获取字符串输入，例如：“从前”，然后报告字符串包含多少大小写字母：

输出示例：字符串有8个大写字母 字符串有5个小写字母，我应该使用字符串类而不是数组，关于如何开始使用这个字符串有什么提示吗？提前感谢，以下是我到目前为止所做的：D

import java.util.Scanner;
public class q36{
    public static void main(String args[]){

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Give a string ");
        String input=keyboard.nextLine();

        int lengde = input.length();
        System.out.println("String: " + input + "\t " + "lengde:"+ lengde);

        for(int i=0; i<lengde;i++) {
            if(Character.isUpperCase(CharAt(i))){

            }
        }
    }
}

Answer 1

使用正则表达式：

public Counts count(String str) {
    Counts counts = new Counts();
    counts.setUpperCases(str.split("(?=[A-Z])").length - 1));
    counts.setLowerCases(str.split("(?=[a-z])").length - 1));
    return counts;
}

Answer 2

您可以尝试以下代码：

public class ASCII_Demo
{
    public static void main(String[] args)
    {
        String str = "ONCE UPON a time";
        char ch;
        int uppercase=0,lowercase=0;
        for(int i=0;i<str.length();i++)
        {
            ch = str.charAt(i);
            int asciivalue = (int)ch;
            if(asciivalue >=65 && asciivalue <=90){
                uppercase++;
            }
            else if(asciivalue >=97 && asciivalue <=122){
                lowercase++;
            }
        }
        System.out.println("No of lowercase letter : " + lowercase);
        System.out.println("No of uppercase letter : " + uppercase);
    }
}

Answer 3

只需创建在找到小写或大写字母时递增的计数器，如下所示：

for (int k = 0; k < input.length(); k++) {
    /**
     * The methods isUpperCase(char ch) and isLowerCase(char ch) of the Character
     * class are static so we use the Class.method() format; the charAt(int index)
     * method of the String class is an instance method, so the instance, which,
     * in this case, is the variable `input`, needs to be used to call the method.
     **/
    // Check for uppercase letters.
    if (Character.isUpperCase(input.charAt(k))) upperCase++;

    // Check for lowercase letters.
    if (Character.isLowerCase(input.charAt(k))) lowerCase++;
}

System.out.printf("There are %d uppercase letters and %d lowercase letters.",upperCase,lowerCase);

Answer 4

Java8中的解决方案：

private static long countUpperCase(String s) {
    return s.codePoints().filter(c-> c>='A' && c<='Z').count();
}

private static long countLowerCase(String s) {
    return s.codePoints().filter(c-> c>='a' && c<='z').count();
}

Answer 5

import java.io.*;
import java.util.*;
public class CandidateCode {
    public static void main(String args[] ) throws Exception {
         int count=0,count2=0,i;
        Scanner sc = new Scanner(System.in);
         String s = sc.nextLine();
         int n = s.length();
         for( i=0; i<n;i++){
             if(Character.isUpperCase(s.charAt(i)))
                 count++;
             if(Character.isLowerCase(s.charAt(i))) 
             count2++;
         }
             System.out.println(count);
             System.out.println(count2);
         }



}

Answer 6

Java8

private static long countUpperCase(String inputString) {
        return inputString.chars().filter((s)->Character.isUpperCase(s)).count();
    }

    private static long countLowerCase(String inputString) {
        return inputString.chars().filter((s)->Character.isLowerCase(s)).count();
    }