Gabor Grothendieck wrote:
> On Mon, Dec 1, 2008 at 12:20 AM, Wacek Kusnierczyk
> <[EMAIL PROTECTED]> wrote:
>
>> Gabor Grothendieck wrote:
>>
>>> Try this:
>>>
>>>
>>>
vec <- c("", "baaa", "bbaa", "bbba", "baamm", "aa")
>>>
grep("^(?!(.)\\1{1,}
On Mon, Dec 1, 2008 at 12:20 AM, Wacek Kusnierczyk
<[EMAIL PROTECTED]> wrote:
> Gabor Grothendieck wrote:
>> Try this:
>>
>>
>>> vec <- c("", "baaa", "bbaa", "bbba", "baamm", "aa")
>>>
>>
>>
>>> grep("^(?!(.)\\1{1,}$).*(.)\\2{1,}$", vec, perl = TRUE)
>>>
>
> or even
>
> grep("^(?!(.)\\1+$).*(.)
On Sun, Nov 30, 2008 at 9:59 PM, Stefan Evert <[EMAIL PROTECTED]> wrote:
> Still, I think it's better to write a few lines of R code than to abuse
> regular expressions to do something they were never intended to do. How do
> other people on this list feel about that issue?
>
Honestly, I believe
Gabor Grothendieck wrote:
> Try this:
>
>
>> vec <- c("", "baaa", "bbaa", "bbba", "baamm", "aa")
>>
>
>
>> grep("^(?!(.)\\1{1,}$).*(.)\\2{1,}$", vec, perl = TRUE)
>>
or even
grep("^(?!(.)\\1+$).*(.)\\2+$", vec, perl = TRUE)
vQ
__
But is there a one-line grep thingy to do this?
Can't think of a one-liner, but a three-line solution you can easily
enough wrap in a small function:
vec<-c("", "baaa", "bbaa", "bbba", "baamm", "aa")
idx.1 <- grep("(.)\\1$", vec)
idx.2 <- grep("^(.)\\1*$", vec)
vec[setdiff(idx.1, idx.2)]
Here is a very slight further simplification, i.e. we can drop the final {1,}
> grep("^(?!(.)\\1{1,}$).*(.)\\2$", vec, perl = TRUE)
[1] 2 3 5
On Sun, Nov 30, 2008 at 3:26 PM, Gabor Grothendieck
<[EMAIL PROTECTED]> wrote:
> Try this:
>
>> vec <- c("", "baaa", "bbaa", "bbba", "baamm", "aa")
>
Try this:
> vec <- c("", "baaa", "bbaa", "bbba", "baamm", "aa")
> grep("^(?!(.)\\1{1,}$).*(.)\\2{1,}$", vec, perl = TRUE)
[1] 2 3 5
The (?...) succeeds only if the string is not all the same
character and since that consumes no characters it
restarts at the beginning to match anything follow
Hi Stefan! :-)
From tools where negative lookbehind can involve variable lengths,
one
would think this would work:
grep("(?
It's really the PCRE library that doesn't like your regexp, not R.
The problem is that negative behind is only possible with a fixed-
length expression, and sinc
Hi all
I have the following regular expression problem: I want to find
complete elements of a vector that end in a repeated character but
where the repetition doesn't make up the whole word. That is, for the
vector vec:
vec<-c("", "baaa", "bbaa", "bbba", "baamm", "aa")
I would like to get
"b
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