R-alpha: R-beta: regex

[Thomas Lumley]

On 22 May 1997, Peter Dalgaard BSA wrote:
> 
> In what connection? In egrep, consider taking some of them out:
> 

I meant the grep() function in R (which needs \ to be quoted)
 grep("([A-Za-z][^:]*):\1","Ac:Ac",value=T)
character(0)
> grep("([A-Za-z][^:]*):\\1","Ac:Ac",value=T)
character(0)
> grep("([A-Za-z][^:]*):\\\1","Ac:Ac",value=T)
character(0)
> 
but
> grep("([A-Za-z][^:]*):","Ac:Ac",value=T)
[1] "Ac:Ac"


Thomas Lumley
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