Positive Lookbehind with commas separated list

Question

I am a Java developer and I am new to Regex, I have similar problem as here in Stackoverflow . I have 2 issues,

• SKIP does not work in Java
• I started following the second approach as per this Regex link but my use case is as below,

if I have a string like,

It is very nice in summer and in summer time we swim, run, tan

It should extract based on Positive lookbehind, "summer time we", it should extract, [smim, run, tan] as an array.

I am stuck here, please help.

Answer 1

In Java, a regex cannot by itself return an array.

But, this regex will return the values you want using a find() loop:

(?<=summer time we |\G(?<!^), )\w+

It is almost identical to the second answer that you referred to.

In Java 9+, you can create array like this:

String s = "It is very nice in summer and in summer time we swim, run, tan";
String[] results = Pattern.compile("(?<=summer time we |\\G(?<!^), )\\w+")
                          .matcher(s).results().map(MatchResult::group)
                          .toArray(i -> new String[i]);
System.out.println(Arrays.toString(results));

Output

[swim, run, tan]

In Java 5+, you can do it with a find() loop:

String s = "It is very nice in summer and in summer time we swim, run, tan";
List<String> resultList = new ArrayList<String>();
Pattern regex = Pattern.compile("(?<=summer time we |\\G(?<!^), )\\w+");
for (Matcher m = regex.matcher(s); m.find(); )
    resultList.add(m.group());
String[] results = resultList.toArray(new String[resultList.size()]);
System.out.println(Arrays.toString(results));