如何计算 java 中字符串中的标点符号？

Question

我需要编写一个程序来计算字符串中的某些标点符号。我有这段我认为可行的代码，但在每个字符处，我都有一个错误，指出赋值的左手必须是一个变量。需要帮助解决此问题

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

    System.out.println("Enter a string: ");
    String s = kbd.next();

    countPunctuation(s);
}
public static int countPunctuation(String s)
{
    int periodCount = 0;
    int commaCount = 0;
    int semicolonCount = 0;
    int colonCount = 0;
    int exclamationCount = 0;
    int questionCount = 0;
    int total = 0;


    for(int i = 0; i < s.length(); i++)
    {
        if(s.charAt(i) = ".")
        {
            periodCount++;
            total++;
        }
        if(s.charAt(i) = ",")
        {
            commaCount++;
            total++;
        }
        if(s.charAt(i) = ";")
        {
            semicolonCount++;
            total++;
        }
        if(s.charAt(i) = ":")
        {
            colonCount++;
            total++;
        }
        if(s.charAt(i) = "!")
        {
            exclamationCount++;
            total++;
        }
        if(s.charAt(i) = "?")
        {
            questionCount++;
            total++;
        }

    }

    System.out.println("There are " + periodCount + " periods in this String.");
    System.out.println("There are " + commaCount + " commas in this String.");
    System.out.println("There are " + semicolonCount + " semicolons in this String.");
    System.out.println("There are " + colonCount + " colons in this String.");
    System.out.println("There are " + exclamationCount + " exclamation marks in this String.");
    System.out.println("There are " + questionCount + " quesiton marks in this String.");


    return total;
}

Answer 1

相等性检查是 == 而不是 =。你需要有类似 if(s.charAt(i) == '.') 的东西，或者你可以在这种情况下使用开关：

for(int i = 0; i < s.length(); i++) {
    switch(s.charAt(i)) { 
     case '.':
        periodCount++;
        break;
     case ',':
        commaCount++;
        break;
     ... // similar conditions for others
    }
    total += 1;
}

Answer 2

不知道这是否有帮助，但我发现了一个小错误

变化：

String s = kbd.next();

收件人：

String s = kbd.nextLine();

我认为这绝对应该解决它。

为什么？：

next();        -is mostly used for characters, as it doesn't get the whole line.
nextLine();    -gets the entire line, which for your code, you'd want.

就像那个人说的，你正在使用

=   -instead of-   ==

"=" 用于分配的变量和东西 “==”是检查，比如 if (String s == ";")

如何计算 java 中字符串中的标点符号？

How to count punctuation marks in a String in java?

java

methods

count

punctuation