字符串中字符出现百分比的错误计算（java）

Question

我的代码获取一个字符串，计算字母表中每个字符在字符串中出现的次数，然后显示数组的直方图以及该字符在字符串中出现次数的百分比信息。

我的代码有问题，没有为字符串中出现的每个字符显示正确的百分比，它偏离了几个百分点。

例如，如果我输入“hello world”，L 应该占字符串的 30%，对吧？但我的代码说它占字符串的 27%。我不太确定这是代码问题还是计算问题

 public class LetterCounter {
    private static int[] alphabetArray; 
    private static char ch; 
    double stringLength; 



    /**
     * Creates an array to hold the total number of occurences for each character of the alphabet
     */
    public LetterCounter()
    {
        alphabetArray = new int[26]; 
    }

    /**
     * The method will go through the user inputted string, incrementing characters one by one 
     * when it comes across them in the string. 
     * @param input: the string that the user wants
     */
    public void countLetters(String input) {
        String userInput= input; 
        String s2 = userInput.toLowerCase();
        for ( int i = 0; i < s2.length(); i++ ) {
            char ch=  s2.charAt(i);
            if (ch >= 97 && ch <= 122){
                alphabetArray[ch-'a']++;
            }
        }
        stringLength = s2.length(); 
    }

    /**
     * Calculates how many characters there are in the inputted string. Multiple strings that are input by the user will be 
     * added to the total character count. 
     * @return: the sum of how many characters there are in each string
     */
    public int getTotalCount() {
        int sum=0; 
        for (int i = 0; i < alphabetArray.length; i++) {
            if(alphabetArray[i]>=0){
                sum = 0; 
                char ch = (char) (i+97); 
                for(int total : alphabetArray) {
                    sum += total;  
                }         
            }

        }
        return sum; 
    }

    /**
     * This method will reset the character count to zero for every character. 
     */
    public void reset() {
        for (int i : alphabetArray) {
            if(alphabetArray[i]>=0){
                alphabetArray[i]=0; 
                char ch = (char) (i+97); 
                System.out.println(ch +"  : "+alphabetArray[i]);   
            }    
        }
    }

    /**
     * The method prints out a histogram of the entire array, displaying the most commonly occuring letter as having 60 #s,
     * with the rest of the letter's #s to the 60 #s. The percentage occurence of each character in the string is also displayed beside the character. 
     * @return: the histogram of the array
     */
    public String toString() {
        int max = alphabetArray[0]; 
        int markCounter = 0;
        double percent = 0.0; 
        String s = ""; 

        for(int i =0; i<alphabetArray.length; i++) {
            //finds the largest number of occurences for any letter in the string
            if(alphabetArray[i] > max) {
                max = alphabetArray[i];
            }
        }

        for (int i = 0; i < alphabetArray.length; i++) {
            //percent = (alphabetArray[i] /stringLength) * 100; 
            percent = Math.round((alphabetArray[i] /stringLength ) * 100);
            markCounter = (alphabetArray[i] * 60) / max; 
            if(alphabetArray[i]>=0){
                char ch = (char) (i+97); 
                System.out.print(ch +" : ");   
            }  

            for (int hash =0; hash <markCounter; hash++) {
                System.out.print("#"); 

            }

            if(alphabetArray[i] >= 0){
                    System.out.print(" " + percent + "%"); //+ percent);

            }
            System.out.println(); 

        }

        return s; 
    }
}

Answer 1

您正在使用 string.length() 函数来计算字符串的长度。这个函数也计算字符串长度中的空间。我猜您正在尝试计算字符串中可用总字符的百分比。

您需要计算循环中的字符串长度，在循环中检查每个字符的频率。

public void countLetters(String input) {
    String userInput= input; 
    String s2 = userInput.toLowerCase();
    for ( int i = 0; i < s2.length(); i++ ) {
        char ch=  s2.charAt(i);
        if (ch >= 97 && ch <= 122){
            alphabetArray[ch-'a']++;
            stringLength++; 
        }
    }

}

这样您将获得字符串中的字符总数。

此外，您可能还想确定是否要包含除字母以外的字符。特殊字符也可以是字符串的一部分。根据您的要求，字符串长度计数器将更新。

Answer 2

字符串输入 = EditTextinput.getText().toString(); input = input.replace(" ", "");

有时您只想删除字符串开头或结尾的空格（而不是中间的空格）。如果是这种情况，您可以使用修剪：

input = input.trim();