[R] gsub issue with consecutive pattern finds

[Iago Giné Vázquez]

Hi Iris,

Thank you. Further, very nice solution.

Best,

Iago

On 01/03/2024 12:49, Iris Simmons wrote:
> Hi Iago,
>
>
> This is not a bug. It is expected. Patterns may not overlap. However, there
> is a way to get the result you want using perl:
>
> ```R
> gsub("([aeiouAEIOU])(?=[aeiouAEIOU])", "\\1_", "aerioue", perl = TRUE)
> ```
>
> The specific change I made is called a positive lookahead, you can read
> more about it here:
>
> https://www.regular-expressions.info/lookaround.html
>
> It's a way to check for a piece of text without consuming it in the match.
>
> Also, since you don't care about character case, it might be more legible
> to add ignore.case = TRUE and remove the upper case characters:
>
> ```R
> gsub("([aeiou])(?=[aeiou])", "\\1_", "aerioue", perl = TRUE, ignore.case =
> TRUE)
>
> ## or
>
> gsub("(?i)([aeiou])(?=[aeiou])", "\\1_", "aerioue", perl = TRUE)
> ```
>
> I hope this helps!
>
>
> On Fri, Mar 1, 2024, 06:37 Iago Giné Vázquez<iago.gine using sjd.es>  wrote:
>
>> Hi all,
>>
>> I tested next command:
>>
>> gsub("([aeiouAEIOU])([aeiouAEIOU])", "\\1_\\2", "aerioue")
>>
>> with the following output:
>>
>> [1] "a_eri_ou_e"
>>
>> So, there are two consecutive vowels where an underscore is not added.
>>
>> May it be a bug? Is it expected (bug or not)? Is there any chance to get
>> what I want (an underscore between each pair of consecutive vowels)?
>>
>>
>> Thank you!
>>
>> Best regards,
>>
>> Iago
>>
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>>
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