R help - Sep 2019 - A question on regular expression

Hi,

I am wondering on what is the correct way to select a pattern which goes as -

{"(any character with any length)"}

The expressions " {" " and " "} " both are
included in the pattern.

For example, the lookup of the above pattern in the text "
{"asaf455%"}57573blabla " will result in {"asaf455%"}

Any help will be highly appreciated.

Thanks,

> sub(".*(\\{.*\\}).*", "\\1","ab{cd$ }ed")
[1] "{cd$ }"

Use ".+" instead of ".*" within the {} if you don't want
to return empty
{}'s.

You might wish to use the stringr package for string matching and
manipulation, as it provides a more user friendly and consistent interface
to these tasks.


Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Thu, Sep 12, 2019 at 9:31 AM Christofer Bogaso <
bogaso.christofer at gmail.com> wrote:
> Hi,
>
> I am wondering on what is the correct way to select a pattern which goes
> as -
>
> {"(any character with any length)"}
>
> The expressions " {" " and " "} " both are
included in the pattern.
>
> For example, the lookup of the above pattern in the text "
> {"asaf455%"}57573blabla " will result in
{"asaf455%"}
>
> Any help will be highly appreciated.
>
> Thanks,
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Thanks Bert,

This works, but if in my text there are more than one patterns then
fails to generate desired result.

library(stringr)
str_extract_all(paste("ab{cd$ }ed", "ab{cad$ }ed", collapse
= " "),
".*(\\{.*\\}).*")

This generates below -

[[1]]

[1] "ab{cd$ }ed ab{cad$ }ed"

I was expecting I would get a vector of length 2 with desired pattern.

Where did I make any mistake?

Thanks,

On Thu, Sep 12, 2019 at 10:29 PM Bert Gunter <bgunter.4567 at gmail.com>
wrote:
>
> > sub(".*(\\{.*\\}).*", "\\1","ab{cd$
}ed")
> [1] "{cd$ }"
>
> Use ".+" instead of ".*" within the {} if you don't
want to return empty {}'s.
>
> You might wish to use the stringr package for string matching and
manipulation, as it provides a more user friendly and consistent interface to
these tasks.
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip
)
>
>
> On Thu, Sep 12, 2019 at 9:31 AM Christofer Bogaso <bogaso.christofer at
gmail.com> wrote:
>>
>> Hi,
>>
>> I am wondering on what is the correct way to select a pattern which
goes as -
>>
>> {"(any character with any length)"}
>>
>> The expressions " {" " and " "} " both
are included in the pattern.
>>
>> For example, the lookup of the above pattern in the text "
>> {"asaf455%"}57573blabla " will result in
{"asaf455%"}
>>
>> Any help will be highly appreciated.
>>
>> Thanks,
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.