单词统计

题目：

第0步：输出某个英文文本文件中 26 字母出现的频率，由高到低排列，并显示字母出现的百分比，精确到小数点后面两位。

第1步：输出单个文件中的前 N 个最常出现的英语单词。作用：一个用于统计文本文件中的英语单词出现频率。

设计思想：首先是统计字母，我们应该先把要统计的文件读取，遍历统计字母出现的次数，将大写字母转换为小写字母；统计单词也需要将大写字母转换为小写，只要遇到空格则记为一个单词，遍历一遍统计单词个数。

import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Scanner;
import java.awt.List;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.io.FileOutputStream;  
import java.io.PrintStream;
import java.text.NumberFormat;
public class tongji {
public static void main(String[] args) {
    File src =new File("c:/Harry Potter and the Sorcerer's Stone.txt");
    InputStream is=null;
   try {
    is=new FileInputStream(src);
    int temp;
    int[] p=new int[56];
    while((temp=is.read())!=-1)//当数据为不存在时，返回-1
    {
        char t=(char)temp;
        if(t=='a'||t=='A')
        {
            p[0]++;
        }
        if(t=='b'||t=='B')
        {
            p[1]++;
        }
        if(t=='c'||t=='C')
        {
            p[2]++;
        }
        if(t=='d'||t=='D')
        {
            p[3]++;
        }
        if(t=='e'||t=='E')
        {
            p[4]++;
        }
        if(t=='f'||t=='F')
        {
            p[5]++;
        }
        if(t=='g'||t=='G')
        {
            p[6]++;
        }
        if(t=='h'||t=='H')
        {
            p[7]++;
        }
        if(t=='i'||t=='I')
        {
            p[8]++;
        }
        if(t=='j'||t=='J')
        {
            p[9]++;
        }
        if(t=='k'||t=='K')
        {
            p[10]++;
        }
        if(t=='l'||t=='L')
        {
            p[11]++;
        }
        if(t=='m'||t=='M')
        {
            p[12]++;
        }
        if(t=='n'||t=='N')
        {
            p[13]++;
        }
        if(t=='o'||t=='O')
        {
            p[14]++;
        }
        if(t=='P'||t=='p')
        {
            p[15]++;
        }
        if(t=='q'||t=='Q')
        {
            p[16]++;
        }
        if(t=='r'||t=='R')
        {
            p[17]++;
        }
        if(t=='S'||t=='s')
        {
            p[18]++;
        }
        if(t=='t'||t=='T')
        {
            p[19]++;
        }
        if(t=='u'||t=='U')
        {
            p[20]++;
        }
        if(t=='v'||t=='V')
        {
            p[21]++;
        }
        if(t=='w'||t=='W')
        {
            p[22]++;
        }
        if(t=='X'||t=='x')
        {
            p[23]++;
        }
        if(t=='Y'||t=='y')
        {
            p[24]++;
        }
        if(t=='z'||t=='Z')
        {
            p[25]++;
        }
                        }
    int[] y=new int[26];
    for(int r=0;r<26;r++)
    {
        y[r]=p[r];
    }
    
    int templ=0;
    for(int i=0;i<26;i++) 
    {
    templ+=p[i];
    }
    float qq=(float)templ;
    int te;
    //冒泡排序
    for(int g=0;g<24;g++)
    {
    for(int f=0;f<24-g;f++) 
    {
        if(p[f]<p[f+1])
        {
            te=p[f];
            p[f]=p[f+1];
            p[f+1]=te;
        }
    }}
    for(int j=0;j<26;j++) {
        NumberFormat nt = NumberFormat.getPercentInstance();//获取百分数实例
        nt.setMinimumFractionDigits(2);//保留百分数后两位
        char w=' ';
        for(int b=0;b<26;b++) {
            if(p[j]==y[b]) {
                switch (b) {
                case 0:
                    w='a';
                    break;
                case 1:
                    w='b';
                    break;
                case 2:
                    w='c';
                    break;
                case 3:
                    w='d';
                    break;
                case 4:
                    w='e';
                    break;
                case 5:
                    w='f';
                    break;
                case 6:
                    w='g';
                    break;
                case 7:
                    w='h';
                    break;
                case 8:
                    w='i';
                    break;
                case 9:
                    w='j';
                    break;
                case 10:
                    w='k';
                    break;
                case 11:
                    w='l';
                    break;
                case 12:
                    w='m';
                    break;
                case 13:
                    w='n';
                    break;
                case 14:
                    w='o';
                    break;
                case 15:
                    w='p';
                    break;
                case 16:
                    w='q';
                    break;
                case 17:
                    w='r';
                    break;
                case 18:
                    w='s';
                    break;
                case 19:
                    w='t';
                    break;
                case 20:
                    w='u';
                    break;
                case 21:
                    w='v';
                    break;
                case 22:
                    w='w';
                    break;
                case 23:
                    w='x';
                    break;
                case 24:
                    w='y';
                    break;
                case 25:
                    w='z';
                    break;
                default:
                    break;
                }
            }
            }
        
        float q=(float)p[j];
        System.out.println(w+"---"+nt.format(q/qq));
        //System.out.println(p[j]/templ);
    }
    //System.out.println(templ);
    //System.out.println(p[0]);
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    
    e.printStackTrace();
}finally {
    try {
        is.close();
    } catch (IOException e) {
        e.printStackTrace();
    }}    }}

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.NoSuchFileException;
import java.util.*;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class danci{
    public static void main(String[] args) throws IOException{
        ArrayList<String> AL = new ArrayList<String>();
        try {
            FileInputStream IS = new FileInputStream("c:/Harry Potter and the Sorcerer's Stone.txt");
            Scanner S = new Scanner(IS);
            while(S.hasNextLine()){ 
                StringTokenizer st = new StringTokenizer(StringFunc(S.nextLine()));
                while(st.hasMoreTokens()) {
                    AL.add(st.nextToken());
                }
            }
            IS.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        HashFunc(AL);
    }
    
    //handle the string
    public static String StringFunc(String Str) {
        Str = Str.toLowerCase();
        Str = Pattern.compile("[^A-Za-z]+").matcher(Str).replaceAll(" ");
        return Str;
    }
    
    //put elements in a hashtable and count how many times they appear
    public static void HashFunc(ArrayList<String> AL) {
        HashMap<String, Integer> Hmap = new LinkedHashMap<>();
        Collections.sort(AL);
        for (String temp : AL) {
            Integer count = Hmap.get(temp);
            Hmap.put(temp, (count == null) ? 1 : count + 1);
        }
        Iterator iter = Hmap.entrySet().iterator();
        while (iter.hasNext()) {
            Map.Entry entry = (Map.Entry) iter.next();
            Object key = entry.getKey();
            Object val = entry.getValue();
            System.out.println(val + " " + key);
        }    
    }
}