Question

我想从字符串中替换一个单词，就像string.replace("word", "different word");的工作方式一样，只是有限次数，让我们在字符串中提到单词apple 10次，我希望apples中的5个成为oranges，我怎么能实现这一目标？

另外，如果可能的话，我希望它是随机的，所以它不会从第一个apple开始，而是跳过，例如更改1st, 3rd, 4th, 7th, and 8th apple会发生变化。

谢谢！

Answer 1

我会做随机子串并在那些上使用replaceFirst方法。对于子字符串，请使用substring(int beginIndex)，其中随机开始索引介于0和lengthOfOriginalWord-1-lengthOfWordToReplace间隔之间。

    try {

        String originalWord = "alabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaORANGEalabalaORANGEORANGEaaaaaaa";
        String replacedWord = "ORANGE";
        String replacingWord = "APPLE";
        String substringedWord = "";

        // make sure this is smaller or equal with the number of occurrences, otherwise it's endless loop times
        int numberOfReplaces = 3;
        Random ran = new Random();
        int beginIndex;

        while (numberOfReplaces > 0) {
            // random index between 0 and originalWord.length()-1-replacedWord.length()
            beginIndex = ran.nextInt(originalWord.length()-1-replacedWord.length());
            substringedWord = originalWord.substring(beginIndex);
            if (substringedWord.contains(replacedWord)) {
                originalWord = originalWord.substring(0, beginIndex) + substringedWord.replaceFirst(replacedWord, replacingWord);
                numberOfReplaces--;                 
            }
        }
        System.out.println(originalWord);
    } catch (Exception exc) {
        System.err.println("An error occurred: \n" + exc);
    }

这是运行五次后的输出：

alabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaAPPLEalabalaAPPLEAPPLEaaaaaaa alabalaportocalaAPPLEalabalaportocalaAPPLEalabalaportocalaAPPLEalabalaportocalaORANGEalabalaORANGEORANGEaaaaaaa alabalaportocalaAPPLEalabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaAPPLEalabalaAPPLEORANGEaaaaaaa alabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaORANGEalabalaportocalaAPPLEalabalaAPPLEAPPLEaaaaaaa alabalaportocalaAPPLEalabalaportocalaORANGEalabalaportocalaAPPLEalabalaportocalaAPPLEalabalaORANGEORANGEaaaaaaa

Answer 2

您可以迭代地使用String#indexOf(String str, int fromIndex)来查找要替换的单词的所有起始索引，然后随机选择其中一些索引（例如使用混洗ArrayList<Integer>，或者{{{ 1}}）并使用ArrayList<Integer>#remove(Random#nextInt(ArrayList#size))

的连接调用构造新字符串

String#substring(int beginIndex, int endIndex)

在字符串中随机替换某个单词有限次数| Java的

2 个答案: