使用拆分提取重叠匹配 [英] Extract overlapping matches using split

问题描述

如何使用 String.split（）从输入中提取重叠匹配？

How can I extract overlapping matches from an input using String.split()?

例如，如果试图找到匹配aba：

For example, if trying to find matches to "aba":

String input = "abababa";
String[] parts = input.split(???);

预期产出：

[aba, aba, aba]

推荐答案

String＃split 不会给你重叠的匹配。因为字符串的特定部分只会包含在获得的数组的唯一索引中，而不包含在两个索引中。

String#split will not give you overlapping matches. Because a particular part of the string, will only be included in a unique index, of the array obtained, and not in two indices.

您应该使用模式和匹配类。
您可以使用此正则表达式： -

You should use Pattern and Matcher classes here. You can use this regex: -

Pattern pattern = Pattern.compile("(?=(aba))");

并使用 Matcher #find 方法获取所有重叠的匹配，并打印 group（1）。

And use Matcher#find method to get all the overlapping matches, and print group(1) for it.

上面的正则表达式匹配每个空字符串，然后是 aba ，然后打印第一个捕获的组。现在，因为预见是零宽度断言，所以它不会消​​耗匹配的字符串。因此，您将获得所有重叠的匹配。

The above regex matches every empty string, that is followed by aba, then just print the 1st captured group. Now since look-ahead is zero-width assertion, so it will not consume the string that is matched. And hence you will get all the overlapping matches.

String input = "abababa";
String patternToFind = "aba";

Pattern pattern = Pattern.compile("(?=" + patternToFind + ")");
Matcher matcher = pattern.matcher(input);

while (matcher.find()) {
    System.out.println(patternToFind + " found at index: " + matcher.start());
}

输出： -

aba found at index: 0
aba found at index: 2
aba found at index: 4

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