[R] problem with pattern matching

[Rnewbie]

I have a list of IDs like this:

AB1234
AB4567
AB8901

In my dataset, there are IDs like this:

AB5555
AB7777 /// AB1234
AB4567 /// AB8901 /// AB6666

I used grep(list$ID, dataset$ID, value=T)
It returned only one match, which was the very first match AB7777 ///
AB1234. It seems once the first match was found, the matching procedure just
stopped.



Don MacQueen wrote:
> 
> Perhaps
>    intersect()
> or
>    merge()
> will help. But, like others, I find it difficult to understand 
> exactly what you want. I'd suggest providing a short example with 
> actual ID values.
> 
> -Don
> 
> At 2:36 AM -0700 8/5/09, Rnewbie wrote:
>>I wanted to extract my interested rows from a dataframe. I used:
>>
>>grep(list$ID, dataframe$ID, value=T) #list contains a list of my
interested
>>IDs
>>
>>I got one match in return, which is the very first ID in list. It seems
the
>>matching process just stopped, once the first match was found.
>>
>>
>>
>>David Winsemius wrote:
>>>
>>>
>>>  On Aug 4, 2009, at 11:16 AM, Rnewbie wrote:
>>>
>>>>
>>>>  dear all,
>>>>
>>>>  I got a problem with pattern matching using grep. I extracted a list 
>>>>  of
>>>>  characters from a data frame, and I tried to match this list of 
>>>>  characters
>>>>  to a column from another data frame. In return, I got only one 
>>>>  match, but
>>>>  there should be far more matches. Any ideas what has gone wrong?
>>>
>>>  In general this falls into the category of  a request to "read my 
>>>  mind". One, out of probably an infinite number, of ways to get such a 
>>>  result is to use if()  when you needed ifelse().
>>>
>>>>
>>>>  Another question, if I also want to match the whole of the elements 
>>>>  against
>>>>  the non-initial parts of the elements in another table. Which 
>>>>  command should
>>>>  I use?
>>>
>>>  Cannot even assign a semantic meaning to that one. What is are "non-
>>>  initial parts of the elements of another table"?
>>>
>>>
>>>  ******************************************************************
>>>>   .... provide commented, minimal, self-contained, reproducible code.
>>>  ******************************************************************
>>>>
>>>>  Thanks
>>>
>>>  David Winsemius, MD
>>>  Heritage Laboratories
>>>  West Hartford, CT
>>>
>>>  ______________________________________________
>>>  R-help at r-project.org mailing list
>>>  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.
>>>
>>>
>>
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>>
>>______________________________________________
>>R-help at r-project.org mailing list
>>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.
> 
> 
> -- 
> --------------------------------------
> Don MacQueen
> Environmental Protection Department
> Lawrence Livermore National Laboratory
> Livermore, CA, USA
> 925-423-1062
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
> 
> 

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