java中如何计算以大写字母开头的单词？

Question

I want to make a program that prints the number of words that START with an uppercase letter. So I made two strings str1 = "The deed is done" and str2 = "My name is Bond, JAMES Bond" . For the first string, it printed 1 which is what I wanted. But for the second one it prints 8 instead of 4 because JAMES is capitalized.

    public static void main(String[] args){
        String str1 = "The deed is done";
        String str2 = "My name is Bond, JAMES Bond";

        System.out.println(uppercase(str2));
    }

    public static int uppercase(String str){
        int cnt = 0;

        for(int i = 0; i < str.length(); i++){
            if(Character.isUpperCase(str.charAt(i)))
                cnt++;
        }

        return cnt;
    }

That's what I have so far. How would I make it so that the other letters in that word aren't counted?

Answer 1

You should check the first character of each word in the input string, instead of all characters of the input string.

public static int uppercase(String str){
    int cnt = 0;

    String[] words = str.split(" ");

    for(int i = 0; i < words.length; i++){
        if(Character.isUpperCase(words[i].charAt(0)))
            cnt++;
    }

    return cnt;
}

A more 'declarative approach' could use a Stream

public static long uppercase2(String str){
    return Arrays.stream(str.split(" "))
            .map(word -> word.charAt(0))
            .filter(Character::isUpperCase)
            .count();
}

Answer 2

String str1 = "The deed is done"; String str2 = "My name is Bond, JAMES Bond"; System.out.println(upperCaseCount(str1)); System.out.println(upperCaseCount(str2)); public static int upperCaseCount(String s) { int count = 0; // append a space to cater for empty string and // use regex to split on one or more spaces. for (String word : (s + " ").split("\\s+")) { if (Character.isUpperCase(word.charAt(0))) { count++; } } return count; }

Answer 3

A nice way to do this is with a regex: \\b[AZ] tests for capital letters occurring after a word boundary, so we can just find all matches and count them.

> import java.util.regex.*;
> Pattern p = Pattern.compile("\\b[A-Z]");
> Matcher m = p.matcher("Hi, this is Stack Overflow.");
> int c = 0;
> while(m.find()) { c++; }
> c
3

Answer 4

I want to make a program that prints the number of words that START with an uppercase letter. So I made two strings str1 = "The deed is done" and str2 = "My name is Bond, JAMES Bond" . For the first string, it printed 1 which is what I wanted. But for the second one it prints 8 instead of 4 because JAMES is capitalized.

    public static void main(String[] args){
        String str1 = "The deed is done";
        String str2 = "My name is Bond, JAMES Bond";

        System.out.println(uppercase(str2));
    }

    public static int uppercase(String str){
        int cnt = 0;

        for(int i = 0; i < str.length(); i++){
            if(Character.isUpperCase(str.charAt(i)))
                cnt++;
        }

        return cnt;
    }

That's what I have so far. How would I make it so that the other letters in that word aren't counted?