Is it possible to define a part of the pattern once then perhaps name it so that it can be reused multiple times inside the main pattern without having to write it out again?
To paint a picture, my pattern looks similar to this (pseudo regex pattern)
(PAT),(PAT), ... ,(PAT)
Where PAT
is some lengthy pattern.
Requirements
([a-z]),([a-z]),([a-z])
then a,a,a
and a,b,c
should matchI've looked into naming the first capturing group then referencing it in the subsequent capturing groups but this method breaks the second requirement (i.e., it fails to match a,b,c
). Is there a direct or indirect way of fulfilling both requirements using regex only?
My end goal is to be able to get and access the value of each capturing group so I can manipulate each group later in the "replace" part of the search & replace box.
"Capturing a repeated group captures all iterations." In your regex101 try to replace your regex with (\w+),? and it will give you the same result. The key here is the g flag which repeats your pattern to match into multiple groups.
A repeat is an expression that is repeated an arbitrary number of times. An expression followed by '*' can be repeated any number of times, including zero. An expression followed by '+' can be repeated any number of times, but at least once.
Capturing groups are a way to treat multiple characters as a single unit. They are created by placing the characters to be grouped inside a set of parentheses. For example, the regular expression (dog) creates a single group containing the letters "d" "o" and "g" .
What is Group in Regex? A group is a part of a regex pattern enclosed in parentheses () metacharacter. We create a group by placing the regex pattern inside the set of parentheses ( and ) . For example, the regular expression (cat) creates a single group containing the letters 'c', 'a', and 't'.
To reuse a pattern, you could use (?n)
where n
is the number of the group to repeat. For example, your actual pattern :
(PAT),(PAT), ... ,(PAT)
can be replaced by:
(PAT),(?1), ... ,(?1)
(?1)
is the same pattern as (PAT)
whatever PAT
is.
You may have multiple patterns:
(PAT1),(PAT2),(PAT1),(PAT2),(PAT1),(PAT2),(PAT1),(PAT2)
may be reduced to:
(PAT1),(PAT2),(?1),(?2),(?1),(?2),(?1),(?2)
or:
((PAT1),(PAT2)),(?1),(?1),(?1)
or:
((PAT1),(PAT2)),(?1){3}
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