REGEX：在Octave上使用命名组替换字符串

Question

I'm aware of the Pythonic way to replace a pattern in a String using named groups:

r"(?P<p>(\.+))".sub(r' \g<p> ', 'test sentence..')

Is it possible to do it on Octave (I'm using v3.8.0)? I tried some variations, as below, but no success.

regexprep('test sentence..', '(?<p>(\.+))', ' \k<p> ')
regexprep('test sentence..', '(?<p>(\.+))', ' $<p> ')

As you may have notice, this simple example focus on capturing the String '..' and adding a space before and after it.

Input: 'test sentence..'
Expected Output: 'test sentence .. '
Group Match: p = '..'

I'm able to capture the match normally using $1 , $2 , etc but not as named token.

Answer 1

With @horchler help, we have narrowed down the problem and it seems only Octave present the described problem. From Octave documentation, we have:

Built-in Function: outstr = regexprep (string, pat, repstr) Built-in Function: outstr = regexprep (string, pat, repstr, "opt1", ...) Replace occurrences of pattern pat in string with repstr.

The pattern is a regular expression as documented for regexp. See regexp.

The replacement string may contain $i, which substitutes for the ith set of parentheses in the match string. For example,

  regexprep ("Bill Dunn", '(\\w+) (\\w+)', '$2, $1') returns "Dunn, Bill" 

Options in addition to those of regexp are

'once' Replace only the first occurrence of pat in the result. 'warnings' This option is present for compatibility but is ignored.

So, they do not mention any support to Named Tokens as MATLAB documentation does. This makes me believe the current version of Octave does not support them along with regexprep function. As far as I know, a major concern of Octave developers is to make sure all MATLAB functionality is there at all, but it seems that one is still not supported.