如何获取特定单词前面的字符串部分的字数？ [关闭]

Question

给定一个特定的字符串和该字符串中出现的特定单词，如何计算该单词之前的单词数？

例如，鉴于句子“我住在农场的红房子里”和“红色”这个词，我怎么能确定这个词前面有多少个单词呢？我想创建一个函数，将原始String和目标字作为参数，并打印如下语句：

在“red”之前有4个单词

Answer 1

只需找到指定单词的索引并使用substring方法。然后按空格分割该子字符串以获取单词数组：

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

Answer 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); 
  } 
}