Java:获取字符串中匹配位置的方法? [英] Java: method to get position of a match in a String?

问题描述

String match = "hello";
String text = "0123456789hello0123456789";

int position = getPosition(match, text); // should be 10, is there such a method?

推荐答案

执行此操作的方法系列是:

The family of methods that does this are:

• int indexOf(String str)
  • indexOf(String str, int fromIndex)
  • lastIndexOf(String str, int fromIndex)

  返回此字符串中第一次(或最后)出现的指定子字符串的索引[从指定索引开始向前(或向后)搜索].

  Returns the index within this string of the first (or last) occurrence of the specified substring [searching forward (or backward) starting at the specified index].

  <小时>

  String text = "0123hello9012hello8901hello7890";
  String word = "hello";
  
  System.out.println(text.indexOf(word)); // prints "4"
  System.out.println(text.lastIndexOf(word)); // prints "22"
  
  // find all occurrences forward
  for (int i = -1; (i = text.indexOf(word, i + 1)) != -1; i++) {
      System.out.println(i);
  } // prints "4", "13", "22"
  
  // find all occurrences backward
  for (int i = text.length(); (i = text.lastIndexOf(word, i - 1)) != -1; i++) {
      System.out.println(i);
  } // prints "22", "13", "4"
  

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