R help - Aug 2019 - parsing files with "\" character

Is there any way to parse files that include the \ character in a string?

When I try to use grep to extract strings with a pattern that includes
"\"
it fails.

If there is no way to do it with R, is it possible with python or a bash
script?

Thank you,

April

	[[alternative HTML version deleted]]

Dear April

Can you show us an example of what you are trying to do and how it 
fails? There are rules about backspaces but I find that if one backspace 
does not work try two, three, four until it works. It would be better to 
understand the rules but life is short.

Michael

On 27/08/2019 06:56, April Ettington wrote:
>   Is there any way to parse files that include the \ character in a string?
> 
> When I try to use grep to extract strings with a pattern that includes
"\"
> it fails.
> 
> If there is no way to do it with R, is it possible with python or a bash
> script?
> 
> Thank you,
> 
> April
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.
> 
> ---
> This email has been checked for viruses by AVG.
> https://www.avg.com
> 
> 
-- 
Michael
http://www.dewey.myzen.co.uk/home.html

The principles of regex are basically the same between R and those other
languages, so I don't see why you would switch... but if you did, asking
here would be inappropriate.

I think the short answer is yes, but can't be specific without a
reproducible example. ([1] is recommended but not required.)

Keep in mind that R has a syntax for strings that uses \ for escaping the
following character. Thus, "\\" is a single-character string with a
backslash in it. However, grep also uses backslash for escaping, so if you want
to search for a single backslash in a target string then grep needs two
backslashes, but each of those has to be escaped in an R string so you would use
four backslashes in R source code strings to match one in the target.

[1] package reprex

On August 26, 2019 10:56:24 PM PDT, April Ettington <aprilettington at
gmail.com> wrote:
>Is there any way to parse files that include the \ character in a
>string?
>
>When I try to use grep to extract strings with a pattern that includes
>"\"
>it fails.
>
>If there is no way to do it with R, is it possible with python or a
>bash
>script?
>
>Thank you,
>
>April
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>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.
-- 
Sent from my phone. Please excuse my brevity.