Question

Text : “aaaa”

Pattern : “aa”

then will two match: aa(0,1), aa(2,3)

if I want three match : aa(0,1), aa(1,2), aa(2,3). (I believe this is a classical problem I don’t know how to describe this :'( )

How can I do it in java or python or others?

Answer 1

See this code here:

String str = "aaaa";
Pattern p1= Pattern.compile("(aa)");
Matcher matcher = p.matcher(str);
int start = -1;
while(matcher.find(start + 1)) {
    start = matcher.start(0);
    System.out.println("Found: " + start);
}

It outputs:

Found: 0
Found: 1
Found: 2

This is basically how you manipulate from where to search the next match in java. Hopefully this will help you.