[R] how to use substring match as condition?

[Charles C. Berry]

On Thu, 29 May 2008, Albert Vilella wrote:

> Hi,
>
> How can I use a substring match as a condition in a subset command?
>

Perhaps

 	subset(input, field1=="blah1" & regexpr("blah2",field3) != -1 )

??

Study in

 	example(gsub)

the regexpr example

and in

 	?gsub

the 'Value' section as it pertains to regexpr.


HTH,

Chuck

> Sth like this:
>
> subset(input, field1=="blah1" & field2=="blah2") # but now with substring
> match in field2
>
> subset(input, field1=="blah1" & field3 *substringmatch* "blah3")
>
> I've tried with gsub, but it won't work:
>
> subset(input, field1=="blah1" & gsub("blah3","",input$field3))
>
> 	[[alternative HTML version deleted]]
>
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Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901