Question

我正在学习自动化面试的Java编码。问题很简单。

写入一个字符串中的单词显示次数。

我完美地写出了代码（或者我以为如此），但是我在终端中得到了一个奇怪的输出。

代码：

import java.util.HashMap;
import java.util.Map;

public class TimesAWordAppearsInString {

    public static void main(String[] args) {
        // TODO Auto-generated method stub


        //step 1. Declare sentence to be used in this class 
        String str ="I am learning learning java java programming";

        //step 2.Create HashMap here! To count the amount times a word appears in the sentence 
        Map<String,Integer> map=new HashMap<String,Integer>();

        //step 2a Get the HashMap to Count from starting place 
        Integer count = 1;

        //step3.Split the string to include the spaces by converting it into an ARRAY (arr)
        String[] arr=str.split(" ");

        //step 4. Using the for...IF....else loop count the number of words in this string
        for(int i=0; i<arr.length;i++){

            //4a. How many times the word occurs 

               //4a.1 starting the process of counting the number times a word
                 //appear in the array and its duplicates.  If there is a duplicate words use ELSE!
              if(!map.containsKey(arr[i])){
                  map.put(arr[i], count);

              }else{
                  map.put(arr[i], map.get(arr[i])+1); //get instance of the duplicate and increase by 1 for occurrence
              }
              //5.printout of string output
              //5.1. go into the String and printout the word
               for(String x:map.keySet()){
                   System.out.println("The count for word :"+x+"="+map.get(x));
               }




        }

    }

}

输出是奇怪的，不是我所期望的。

我期待的是：

Java单词数= 3 字数I = 1 计数学习= 2

等。得到的是下面显示的内容。再来一次。我做错了什么？

输出。

The count for word :I=1
The count for word :I=1
The count for word :am=1
The count for word :I=1
The count for word :learning=1
The count for word :am=1
The count for word :I=1
The count for word :learning=2
The count for word :am=1
The count for word :java=1
The count for word :I=1
The count for word :learning=2
The count for word :am=1
The count for word :java=2
The count for word :I=1
The count for word :learning=2
The count for word :am=1
The count for word :java=2
The count for word :I=1
The count for word :learning=2
The count for word :am=1
The count for word :programming=1

Answer 1

您已将您的2nd for循环放在第一个循环中。更新如下：

import java.util.HashMap;
import java.util.Map;

public class TimesAWordAppearsInString {

    public static void main(String[] args) {
        // TODO Auto-generated method stub


        //step 1. Declare sentence to be used in this class 
        String str ="I am learning learning java java programming";

        //step 2.Create HashMap here! To count the amount times a word appears in the sentence 
        Map<String,Integer> map=new HashMap<String,Integer>();

        //step 2a Get the HashMap to Count from starting place 
        Integer count = 1;

        //step3.Split the string to include the spaces by converting it into an ARRAY (arr)
        String[] arr=str.split(" ");

        //step 4. Using the for...IF....else loop count the number of words in this string
        for(int i=0; i<arr.length;i++){

            //4a. How many times the word occurs 

               //4a.1 starting the process of counting the number times a word
                 //appear in the array and its duplicates.  If there is a duplicate words use ELSE!
              if(!map.containsKey(arr[i])){
                  map.put(arr[i], count);

              }else{
                  map.put(arr[i], map.get(arr[i])+1); //get instance of the duplicate and increase by 1 for occurrence
              }

        }

          //5.printout of string output
          //5.1. go into the String and printout the word
           for(String x:map.keySet()){
               System.out.println("The count for word :"+x+"="+map.get(x));
           }

    }

}

Answer 2

似乎您正在使用较大的for循环的每次迭代打印出哈希图的输出（如下所示的循环）以向地图添加计数。

for(String x:map.keySet()){
     System.out.println("The count for word :"+x+"="+map.get(x));
}

尝试将其移至循环之外，您将看到所需的结果。

计算Java字符串中的重复单词。奇数终端显示

2 个答案: