問題描述

我想制作一個 java 程序來讀取一個文本文件并存儲每個出現的字符.所以它會考慮標點符號、字母、數字、大寫、小寫等.給定一個文本文件，例如:

I would like to make a java program that will read a text file and store every single character occurrence. So it will account for punctuation, letters, numbers,uppercase, lowercase ect. Given a text file like:

玫瑰是紅色的，

紫羅蘭色是藍色的.

打印值如下所示:

R : 1

r : 3

我:1

, : 1

[等]

到目前為止，我能夠讀取文件并計算字數、行數和字符數.

So far I am able to read a file and count words, lines, chars.

package Exercise3;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.io.*;
    public class StringTokenizerDemo1
    {
        public static void main(String[] args) throws IOException
        {
            Scanner keyboard = new Scanner(System.in);
            File file = new File("C://Users//guy//Desktop//Practice.txt");
            Scanner inputFile = new Scanner(file);
            String line, word;
            StringTokenizer token;
            int words = 0; //word count 
            int lines = 0; //line count
            int chars = 0; //char count 
            while (inputFile.hasNext())
            {
                lines++; //add one to line count 
                line = inputFile.nextLine();
                token = new StringTokenizer(line, " ");
                while (token.hasMoreTokens())
                {
                    words++; //add one word count 
                    word = token.nextToken();
                    chars+= word.length(); //add to char count 
                }
            }
        }
    }

我沒有學過哈希圖/表或樹圖；尋找一些關于如何使用數組、數組列表或鏈接列表存儲所有字符類型及其出現的建議.

I have not learned hash maps/tables or treemaps; looking for some advice on how to store all char types and their occurrences either using an array,arraylist or linkedlist.

推薦答案

一個 char 是一個 16 位無符號值，如果你將它轉換為一個 int，那么你會得到一個介于 0 和 65535 之間的值.這意味著你可以只使用一個數組來存儲你的字符:

A char is a 16-bit unsigned value, and if you cast it to an int, then you'll get a value between 0 and 65535. That means that you can just use an array to store your characters:

int[] charCounts = new int[65536];

然后當你想記錄 char c 的出現時:

and then when you want to record an occurrence of char c:

charCounts[(int) c]++;

當您想讀取計數時:

for (int i=0; i<65536; i++)
    if (charCounts[i]>0)
        System.out.println((char)(i)+": "+charCounts[i]);

如果您想將其作為練習進行，則沒有什么可以阻止您使用 HashMap<Character,Integer> 進行此操作，盡管它比為此需要的重量更大:p>

There is nothing to stop you doing it with a HashMap<Character,Integer> if you want to do it as an exercise, though it's more heavyweight than it needs to be for this:

HashMap<Character,Integer> map = new HashMap<Character,Integer>();

當你要記錄char c的出現時:

if (!map.containsKey(c))
    map.put(c,1);
else
    map.put(c,map.get(c)+1);

當你想閱讀時:

for (Map.Entry<Character,Integer> entry: map.entrySet())    
    System.out.println(entry.getKey()+": "+entry.getValue());

請注意，對于所有這些，我假設您只處理可打印字符.如果沒有，當你打印出來時，你會想要做一些事情.

Note that for all of this I've assumed you're dealing only with printable characters. If not, you'll want to do something about that when you print them out.

這篇關于讀取文本文件并存儲出現的每個字符的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！