[R] element wise pattern recognition and string substitution
jdnewmil at dcn.davis.ca.us
Mon Sep 5 17:37:08 CEST 2016
Yes, sorry I did not look closer... regex can match any finite language, so there are no data sets you can feed to R that cannot be matched.  You may find it hard to see the pattern, or you may want to build the pattern programmatically to alleviate tedium for yourself, but regexes are not the constraint.
Sent from my phone. Please excuse my brevity.
On September 4, 2016 10:41:45 PM PDT, Bert Gunter <bgunter.4567 at gmail.com> wrote:
>Well, he did provide an example, and...
>> z <- c('TX.WT.CUT.mean','mg.tx.cv')
> "WT.CUT" "tx"
>## seems to do what was requested.
>Jeff would have to amplify on his initial statement however: do you
>mean that separate patterns can always be combined via "|" ? Or
>"The trouble with having an open mind is that people keep coming along
>and sticking things into it."
>-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>On Sun, Sep 4, 2016 at 9:30 PM, Jeff Newmiller
><jdnewmil at dcn.davis.ca.us> wrote:
>> Your opening assertion is false.
>> Provide a reproducible example and someone will demonstrate.
>> Sent from my phone. Please excuse my brevity.
>> On September 4, 2016 9:06:59 PM PDT, Jun Shen <jun.shen.ut at gmail.com>
>>>I have a vector of strings that cannot be described by one pattern.
>>>let's say I construct a vector of patterns in the same length as the
>>>of strings, can I do the element wise pattern recognition and string
>>>pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)"
>>>pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)"
>>>patterns <- c(pattern1,pattern2)
>>>strings <- c('TX.WT.CUT.mean','mg.tx.cv')
>>>Say I want to extract "WT.CUT" from the first string and "tx" from
>>>second string. If I do
>>>sub(patterns, '\\2', strings), only the first pattern will be used.
>>>looping the patterns doesn't work the way I want. Appreciate any
>>> [[alternative HTML version deleted]]
>>>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>PLEASE do read the posting guide
>>>and provide commented, minimal, self-contained, reproducible code.
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> PLEASE do read the posting guide
>> and provide commented, minimal, self-contained, reproducible code.
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