perl regex to capture repeating group

Question

I want a regular expression that matches something at the beginning of a line, and then matches (and returns) all other words. For instance, given this line:

$line = "one two three etc";

I want something like this (that doesn't work):

@matches= $line=~ /^one(?:\s+(\S+))$/;

to return into @matches, the words "two", "three", "etc".

I don't want to know how to get the words. I want to do it with a regular expression. It seems so simple, but I have not been able to come with a solution.

Answer 1

To do that you need to use the \G anchor that matches the position at the end of the last match. When you build a pattern with this anchor, you can obtain contiguous results:

@matches = $line =~ /(?:\G(?!\A)|^one) (\S+)/g; 

Answer 2

You cannot have an unknown number of capture groups. If you try to repeat a capturing group, the last instance will override the contents of the capture group:

• Expression: ^one(?:\s+(\S+))+$
• Capture #1: etc

Or:

• Expression: ^one\s+(\S+)\s+(\S+)\s+(\S+)$
• Capture #1: two
• Capture #2: three
• Capture #3: etc

---

I suggest either capturing the entire group and then splitting by spaces:

• Expression: ^one\s+((?:\S+\s*)+)$
• Capture #1: two three etc

Or you can do a global match and utilize \G and \K:

• Expression: (?:^one|(?<!\A)\G).*?\K\S+
• Match #1: two
• Match #2: three
• Match #3: etc

Answer 3

^.*?\s\K|(\w+)

Try this.See demo.

http://regex101.com/r/lS5tT3/2