capturing-group

I have a list of words: bau ceu diu fou gau I want to turn that list into: byau cyeu dyiu fyou gyau I unsuccessfully tried the command: :%s/(\w)(\w\w)/\1y\2/g Given that this doesn't work, what do I have to change to make the regex capture groups work in Vim? One way to fix this is by ensuring the pattern is enclosed by escaped parentheses: :%s/\(\w\)\(\w\w\)/\1y\2/g Slightly shorter (and more magic -al) is to use \v , meaning that in the pattern after it all ASCII characters except '0'-'9' , 'a'-'z' , 'A'-'Z' and '_' have a special meaning: :%s/\v(\w)(\w\w)/\1y\2/g See: :help \( :help \v If

I have the following regular expression in two different languages that produces the same odd results (javaScript and Flash). What I want to know is not how to fix it, but why the behavior is occurring? The Regular Expression: \[(\\{2}|\\\]|[^\]])*\] The goal here is to match a bracketed string, and ensure that I don't stop at an escaped bracket. If I have the text input [abcdefg] it is correctly matched, but the only thing returned as part of the capture group is g , where as I expect abcdefg . If I change the expression to \[((?:\\{2}|\\\]|[^\]])*)\] , then I get the result that I want. So

Part of a series of educational regex articles, this is a gentle introduction to the concept of nested references. The first few triangular numbers are: 1 = 1 3 = 1 + 2 6 = 1 + 2 + 3 10 = 1 + 2 + 3 + 4 15 = 1 + 2 + 3 + 4 + 5 There are many ways to check if a number is triangular. There's this interesting technique that uses regular expressions as follows: Given n , we first create a string of length n filled with the same character We then match this string against the pattern ^(\1.|^.)+$ n is triangular if and only if this pattern matches the string Here are some snippets to show that this

I want to match a regex like /(a).(b)(c.)d/ with "aabccde" , and get the following information back: "a" at index = 0 "b" at index = 2 "cc" at index = 3 How can I do this? String.match returns list of matches and index of the start of the complete match, not index of every capture. Edit: A test case which wouldn't work with plain indexOf regex: /(a).(.)/ string: "aaa" expected result: "a" at 0, "a" at 2 Note: The question is similar to Javascript Regex: How to find index of each subexpression? , but I cannot modify the regex to make every subexpression a capturing group. So, you have a text

Is there a regex flavor that allows me to count the number of repetitions matched by the * and + operators? I'd specifically like to know if it's possible under the .NET Platform. You're fortunate because in fact .NET regex does this (which I think is quite unique). Essentially in every Match , each Group stores every Captures that was made. So you can count how many times a repeatable pattern matched an input by: Making it a capturing group Counting how many captures were made by that group in each match You can iterate through individual capture too if you want! Here's an example: Regex r =