如何使Java閱讀並計算輸入的句子數

Question

樣本輸出：

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輸入文章：我喜歡貓。 輸入錯誤！ 您的文章必須至少包含2個句子，請重試：

輸入文章：我喜歡貓。 我喜歡狗。

您的文章包含2個句子。

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到目前為止，這是我的代碼：

System.out.print("Enter the essay: ");

String essay = input.nextLine();

do {
    System.out.print("Incorrect input! Your essay must contain at least 2 sentences, please try again: ");
    essay = input.nextLine();
} while (!(essay.contains(".")));

if (essay.contains(".")) {
    System.out.println("Your essay contains x sentences.");
}

差距很多，我不知道該如何去做。 你能幫忙嗎？

Answer 1

您可以使用稍微復雜的正則表達式進行拆分，並取其長度：

Scanner input = new Scanner(System.in);

System.out.print("Enter the essay: ");

String essay = input.nextLine();
int sentenceCount = essay.split("\\S(\\s*[.!?])+(?!\\d)").length;

while (sentenceCount < 2) {
    System.out.print("Incorrect input! Your essay must contain at least 2 sentences, please try again: ");
    essay = input.nextLine();
    sentenceCount = essay.split("\\S(\\s*[.!?])+(?!\\d)").length;
}

System.out.printf("Your essay contains %d sentences.", sentenceCount);

在Ideone上進行現場演示

請注意，這還會計算其他以句子結尾的字符，並拒絕其他顯然不是2個句子的輸入，例如：

• ...
• 我沒有寫一個！
• WTF？！？！
• Pi是3.14159。

Answer 2

這應該可以工作，並且如果您使用Java 8，則不需要countStringOccurrences方法。

import java.util.Scanner;

public class util {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        int count = 0;
        String pattern = ".";

        System.out.print("Enter your sentence:\n");
        String  essay = input.nextLine();

        //this is supported in Java 8 . Otherwise you need to implement method 
        int howmany = countStringOccurrences(essay, pattern);
        System.out.print("how many : " + howmany + "\n");

        while ( !(essay.contains(pattern) ) || howmany < 2) {

            System.out.print("Incorrect input! Your essay must contain at least 2 sentence, please try again:\n ");
            essay = input.nextLine();
            howmany = countStringOccurrences(essay, pattern);
        }

        int i = 0;
        // Keep calling indexOf for the pattern.
        while ((i = essay.indexOf(pattern, i)) != -1) {
            // Advance starting index.
            i += pattern.length();
            // Increment count.
            count++;
        }

        System.out.print("Your essay contains " + count + " sentences");   
    }

    private static int countStringOccurrences(String essay, String pattern) {
        // TODO Auto-generated method stub
        int i = 0;
        int count = 0;
        // Keep calling indexOf for the pattern.
        while ((i = essay.indexOf(pattern, i)) != -1) {
            // Advance starting index.
            i += pattern.length();
            // Increment count.
            count++;
        }

        return count;
    }

}

Answer 3

Scanner scanner = new Scanner(System.in);

System.out.print("Enter the essay: ");
String essay = scanner.nextLine();

while (essay.split("[.]").length < 2) {
    System.out.println("Incorrect input! Your essay must contain at least 2 sentences, please try again: ");
    essay = scanner.nextLine();
}
System.out.println("Your essay contains " + essay.split("[.]").length + " sentences");

Answer 4

使用https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#countMatches(java.lang.String,%20java.lang.String）用於計算“。”的數量 出現在字符串中。

直接取自Javadocs的示例：

計算子字符串出現在較大的String中的次數。

空或空（“”）字符串輸入將返回0。

 StringUtils.countMatches(null, *) = 0 StringUtils.countMatches("", *) = 0 StringUtils.countMatches("abba", null) = 0 StringUtils.countMatches("abba", "") = 0 StringUtils.countMatches("abba", "a") = 2 StringUtils.countMatches("abba", "ab") = 1 StringUtils.countMatches("abba", "xxx") = 0