如何获取特定单词之前的字符串部分的字数？ [关闭]答案

【问题标题】：How to get word count for the part of a String preceding a specific word? [closed]如何获取特定单词之前的字符串部分的字数？ [关闭]
【发布时间】：2019-04-15 18:07:14
【问题描述】：

给定一个特定的字符串和出现在该字符串中的特定单词，我如何计算该单词之前的单词数？

例如，给定句子“I live in a red house on the farm”和“red”这个词，我如何确定这个词之前有多少个词？我想创建一个函数，它将原始字符串和目标单词作为参数并打印如下语句：

“红”字前有4个字

【问题讨论】：

Java: method to get position of a match in a String?的可能重复
试试这个：String str = "I live in a red house on the farm"; String[] array = str.split(" "); int i = 0; for(String x:array){ if (!x.equals("red")){ i++; }else{ break; } } System.out.println("There are " + i + " words before red"); } }
理想情况下，这应该由自然语言处理库来处理。

标签： java string position

【解决方案1】：

只要找到指定单词的索引，使用substring方法即可。然后将该子字符串按空格拆分以获取单词数组：

 String str = "I live in a red house on the farm";
 int count = str.substring(0, str.indexOf("red")).split(" ").length;  // 4

【讨论】：

【解决方案2】：

通常你可以通过 find、search 或 indexOf 函数来做到这一点：

试试看： https://www.geeksforgeeks.org/searching-for-character-and-substring-in-a-string/

// Java program to illustrate to find a character 
// in the string. 
import java.io.*; 

class GFG 
{ 
  public static void main (String[] args) 
  { 
    // This is a string in which a character 
    // to be searched. 
    String str = "GeeksforGeeks is a computer science portal"; 

    // Returns index of first occurrence of character. 
    int firstIndex = str.indexOf('s'); 
    System.out.println("First occurrence of char 's'" + 
                       " is found at : " + firstIndex); 

    // Returns index of last occurrence specified character. 
    int lastIndex = str.lastIndexOf('s'); 
    System.out.println("Last occurrence of char 's' is" + 
                       " found at : " + lastIndex); 

    // Index of the first occurrence of specified char 
    // after the specified index if found. 
    int first_in = str.indexOf('s', 10); 
    System.out.println("First occurrence of char 's'" + 
                       " after index 10 : " + first_in); 

    int last_in = str.lastIndexOf('s', 20); 
    System.out.println("Last occurrence of char 's'" + 
                     " after index 20 is : " + last_in); 

    // gives ASCII value of character at location 20 
    int char_at = str.charAt(20); 
    System.out.println("Character at location 20: " + 
                                             char_at); 

    // throws StringIndexOutOfBoundsException 
    // char_at = str.charAt(50); 
  } 
}

【讨论】：

我试过了，但我试图找到关键字之前的实际字数，而不是索引。