[R] Pattern match

Christofer Bogaso bogaso.christofer at gmail.com
Wed Mar 20 20:00:15 CET 2013


Thanks Mark for your reply. Actually I was looking for following type
of solution:

> grep("(wti)|(asdf)", c("aa", "wti-fgg", "wtihjg", "fdsdasdf", "wti"))
[1] 2 3 4 5


However I was able to find the solution just using grep() function.

On Wed, Mar 20, 2013 at 11:48 PM, Mark Sharp <msharp at txbiomed.org> wrote:
> I like the stringr package. Its functions allow vectors for the patterns.
>
> From the examples of str_detect()
>> fruit <- c("apple", "banana", "pear", "pinapple")
>> str_detect(fruit, "a")
> [1] TRUE TRUE TRUE TRUE
>> str_detect(fruit, "^a")
> [1]  TRUE FALSE FALSE FALSE
>> str_detect(fruit, "a$")
> [1] FALSE  TRUE FALSE FALSE
>> str_detect(fruit, "b")
> [1] FALSE  TRUE FALSE FALSE
>> str_detect(fruit, "[aeiou]")
> [1] TRUE TRUE TRUE TRUE
>>
>> # Also vectorised over pattern
>> str_detect("aecfg", letters)
>  [1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
> [18] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
>
> R. Mark Sharp
> msharp at TxBiomed.org
>
>
>
>
> On Mar 20, 2013, at 11:28 AM, Christofer Bogaso wrote:
>
>> Hello again, in the help page of grep() function, it is written that
>>
>> pattern:
>>
>> character string containing a regular expression (or character string
>> for fixed = TRUE) to be matched in the given character vector. Coerced
>> by as.character to a character string if possible. If a character
>> vector of length 2 or more is supplied, the first element is used with
>> a warning. Missing values are allowed except for regexpr and gregexpr.
>>
>> But I have a vetcor of length '(> 1)' for the pattern match, and I
>> need to have approximate match.
>>
>> Is there any function similar to grep() to handle that?
>>
>> Thanks for your help.
>>
>> ______________________________________________
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>> 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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